Negating an “all” claim yields a “some” claim. Here, “not all mammals are [blah]” translates to “some mammals are not [blah].”

The stimulus features no “some” claims – this quantifier mismatch suffices to eliminate (A). You should aspire to recognize this rapidly and without the need to diagram anything.

This matches the stimulus’ contrapositive argument form:

English
P1: Rural districts don’t have lots of automobiles.
P2: But you need lots of automobiles to have pollution problems.
________
C: Rural districts don’t have pollution problems.

Logic
P1: Rural → /Autos
P2: Problems → Autos
(P2 Contra: /Autos → /Problems)
________
C: Rural → /Problems

Note that I’ve re-ordered (B)’s claims to mirror the order used in the stimulus. That’s totally fine since the underlying logical structure is the same. That different order is for sure part of what makes (B) hard to recognize, though. Get used to it!

The terms “most” and “unlikely” are mismatches in quantity (and likelihood) with the stimulus, which solely features “all” claims (and “definite” claims). These suffice to eliminate (C). You should aspire to recognize them rapidly and without the need to diagram anything.

(D) is wrong for two main reasons. First, there’s a subtle term switch from “receiving profits over and above regular royalties” and “receiving large regular royalties.” Those concepts aren’t the same, so the logical chain (D) attempts has a broken link there. Spotting this spares you the need to diagram.

If you miss that and do diagram, though, (D) is wrong because it exhibits a straightfoward conditional chain that doesn’t do any contrapositivey stuff. Here’s the logic:

Logic
P1: Famous → Record
P2: Record → Profits
________
C: Famous → Profits(ish)

(E) is wrong because of a number of conceptual mismatches between terms. Making clean links between conditional statements means terms need to overlap from one claim to the next. (E) jumps around between the similar sounding, but nevertheless distinct concepts of managers, insiders, people-who-are-known-to-managers, and people-who-are-known-to-insiders.