This establishes that if a fruit is rotten, it’s not safe to eat. But we want to establish what kind of fruit IS safe to eat. An answer establishing that something is NOT safe to eat does not prove that something IS safe to eat. Also, we don’t know whether fruits that are inspected are or are not rotten. So “rotten” doesn’t connect to anything relevant to the conclusion.

We don’t know whether fruits that are inspected are or are not rotten. So (B) doesn’t help establish that fruits that are inspected are safe to eat. You might have mistakenly thought that fruits that are not infected are not rotten — but none of the premises establishes this relationship.

The conclusion concerns fruits that were inspected and that are not infected. What would be true about infected fruits had they been inspected doesn’t affect fruits that were in fact inspected.

We want to establish what kind of fruit IS safe to eat. An answer establishing that something is NOT safe to eat does not prove that something IS safe to eat. (D) leaves open the possibility that it might still be unsafe to eat fruits that are uninfected; those fruits might be unsafe to eat for other reasons unrelated to infection.

(E) establishes that if a fruit is uninfected, it is safe to eat. Since we know that fruits that are inspected are not infected, (E) proves that fruits that are inspected are safe to eat.