This is a Sufficient Assumption question so our job is to add a premise to make the existing argument valid.
It's a very difficult question because you had to realize that they fed you the definition of "prudent" in the premises. The definition is "forming opinions of others only after cautiously gathering and weighing the evidence."
If you can't get over that hurdle, you're likely getting this question wrong.
Assuming you made that connection, then replace that long definition in the premises with the word "prudent" and you should see that this is like any other SA question.
Premise in English: being prudent will make people resent you.
Premise in Lawgic: P --> R
Conclusion in English: appearing prudent is imprudent
Conclusion in Lawgic: P --> Imp
What's the missing SA?
SA in Lawgic: R --> Imp
SA in English: making people resent you is imprudent.
That's (E)
Journalist: Recent studies have demonstrated that a regular smoker who has just smoked a cigarette will typically display significantly better short-term memory skills than a nonsmoker, whether or not the nonsmoker has also just smoked a cigarette for the purposes of the study. Moreover, the majority of those smokers who exhibit this superiority in short-term memory skills will do so for at least eight hours after having last smoked.
Summary
A smoker who has just smoked a cigarette will typically display significantly better short-term memory skills than a nonsmoker, even if the nonsmoker has also just smoked.
Most of these regular smokers will continue to display superior short-term memory skills for at least eight hours after their last cigarette.
Notable Valid Inferences
Most smokers will display better short-term memory skills than will most non-smokers immediately after both parties have smoked a cigarette.
Most smokers will display better short-term memory skills than will most non-smokers immediately after the smoker smoked a cigarette and the nonsmoker did not.
Most smokers will display better short-term memory skills than will most non-smokers for at least eight hours after the smoker’s last cigarette.
A
The short-term memory skills exhibited by a nonsmoker who has just smoked a cigarette are usually substantially worse than the short-term memory skills exhibited by a nonsmoker who has not recently smoked a cigarette.
Could be true. We have no information about how short-term memory skills exhibited by nonsmokers who have not recently smoked a cigarette compare with those exhibited by nonsmokers who have recently smoked, so we can’t conclude that (A) must be false.
B
The short-term memory skills exhibited by a nonsmoker who has just smoked a cigarette are typically superior to those exhibited by a regular smoker who has just smoked a cigarette.
Must be false. This directly refutes the information in the stimulus: we know that the short-term memory skills exhibited by the typical nonsmoker who has just smoked a cigarette will be worse than those exhibited by the typical regular smoker who has just smoked a cigarette!
C
The short-term memory skills exhibited by a nonsmoker who has just smoked a cigarette are typically superior to those exhibited by a regular smoker who has not smoked for more than eight hours.
Could be true. We don’t know how nonsmokers’ short-term memories stack up against smokers’ short-term memories once those smokers have gone over 8 hours without a cigarette!
D
A regular smoker who, immediately after smoking a cigarette, exhibits short-term memory skills no better than those typically exhibited by a nonsmoker is nevertheless likely to exhibit superior short-term memory skills in the hours following a period of heavy smoking.
Could be true. The stimulus does nothing to rule out the possibility that the regular smoker described in (D) could experience a boost in short-term memory skills after smoking heavily, even if their short-term memory skills were not superior immediately after one cigarette.
E
The short-term memory skills exhibited by a regular smoker who last smoked a cigarette five hours ago are typically superior to those exhibited by a regular smoker who has just smoked a cigarette.
Could be true. We have no information about what happens to smokers’ superior short-term memories during the five hours after their last cigarette—maybe they improve before dropping off later!
The Iliad and the Odyssey were both attributed to Homer in ancient times. But these two poems differ greatly in tone and vocabulary and in certain details of the fictional world they depict. So they are almost certainly not the work of the same poet.
Summarize Argument
The author concludes that the Iliad and the Odyssey were almost certainly not written by the same poet. She bases this on the fact that the two poems differ greatly in tone and vocabulary and in their depictions of the fictional world.
Notable Assumptions
The author assumes that, just because two works differ greatly in tone, vocabulary, and other details, they were almost certainly not written by the same person. This means the author assumes that the same writer cannot or would not write two works that differ greatly in these respects.
A
Several hymns that were also attributed to Homer in ancient times differ more from the Iliad in the respects mentioned than does the Odyssey.
We don’t know if Homer actually wrote these hymns that were attributed to him. So, (A) doesn’t tell us anything about whether the same writer could or would write separate works that differ in tone, vocabulary, and other details.
B
Both the Iliad and the Odyssey have come down to us in manuscripts that have suffered from minor copying errors and other textual corruptions.
Just because the Iliad and the Odyssey have suffered from “minor copying errors” doesn’t change the fact that the two poems differ greatly in tone, vocabulary, and other details. So the question of whether they might have been written by the same author remains.
C
Works known to have been written by the same modern writer are as different from each other in the respects mentioned as are the Iliad and the Odyssey.
By presenting works by the same modern writer that differ greatly in tone, vocabulary, and other details, (C) proves that the author’s assumption (that two works that differ in these respects can’t be by the same writer) cannot be true. So, the author’s conclusion doesn’t follow.
D
Neither the Iliad nor the Odyssey taken by itself is completely consistent in all of the respects mentioned.
The fact that parts of a work vary in these ways doesn't answer the question of authorship. Perhaps, for example, the work had multiple authors. We need an answer that addresses the assumption that works with such differences can't have been written by the same person.
E
Both the Iliad and the Odyssey were the result of an extended process of oral composition in which many poets were involved.
By suggesting that many poets contributed to the poems, (E) further argues against the idea that the Iliad and Odyssey were written by a single author. So it doesn't weaken the author's conclusion.