(A) presents a valid argument with no causal claims. The first sentence points to a set of planes (pre-1940 ones) that flew and didn't have jet engines. The conclusion says jet engines aren't necessary to fly planes, which follows from the existence of those pre-1940 jetless planes.

(B) matches the stimulus in taking two correlative claims and drawing an implicit causal conclusion:

Stimulus
Great universities: no admins; endured for centuries
Our universities: hella admins; endurance threatened
—
Let's abolish the admins – that'll ensure our endurance.

(B)
Novelist: computer; published
You: no computer; not published
—
You should use a computer – that'll ensure you get published.

Just because having a computer is correlated with getting published doesn't mean it is the cause.

The fastest way to eliminate (C) is to notice the mismatch in its conclusion. Like the stimulus, premise 1 establishes a negative correlation between two things (antibiotics and infections). To match, (C)'s conclusion should say "let's do [one of those]; that'll ensure [the other one]."

One fast way to eliminate (D) is to notice that the causal language appears in a premise instead of the conclusion. The phrase "a good helmet can save the rider's life" is causal, but it's a premise.

It's a bit foggy whether we should read the first sentence (don't ride bikes helmetless) or the last clause (helmets are important) as the conclusion, but neither of those claims are causal.

(E) presents solid reasoning. Like the stimulus, it begins with a correlation: ancient cities are correlated with waterways. To match, the conclusion should say something like "we should build our city along a waterway [for reasons]."

But the recommendation (E) gives to archaeologists makes sense – they're hunting for cities, so they should look where cities are more likely to be. There's no implication that waterways caused cities or vice versa.