Mismatched premises. (A) presents two facts, neither of which is a conditional statement. The stimulus attempts to read the contrapositive of a conditional statement, so (A) doesn’t match.

Mismatched conclusion. (B) presents a conditional statement (if there is mayo, then it would be in the refrigerator). It then presents evidence that the necessary condition is absent to conclude that the sufficient condition is probably absent. The stimulus, however, presents evidence that a necessary condition is absent to conclude that the sufficient condition is definitely absent, so (B) doesn’t match.

Mismatched premises and conclusion. (C) presents a conditional statement (if Hendricks wins, then the voters care most about fighting crime). It then brings up the new idea of Hendricks’s stance on crime to make a conclusion about what voters will do. The stimulus, however, does not bring up any new information when making its conclusion, so (C) doesn’t match.

Mismatched premises and conclusion. (D) presents a conditional statement (if rodents are to blame for the lost grain, then they will find evidence of rodents). It then concludes that the presence of the necessary condition implies the presence of the sufficient condition. The stimulus, however, attempts to go from the absence of the necessary condition to the absence of the sufficient condition, so (D) doesn’t match.

The argument proceeds by presenting a conditional statement (if the army is planning an attack, then there would be troop movements or weapons transfers). It then tells us that nobody has found evidence of the necessary condition in order to conclude the absence of the sufficient condition (the army is not planning an attack).