Mismatched premises. The stimulus gives a conditional relationship with two sufficient conditions in conjunction, fails the necessary condition, then concludes that either one of the sufficient conditions must fail. (A) gives a conditional relationship with two sufficient conditions in conjunction (if all classes are canceled AND biology lab is a class, then biology lab is canceled), but (A) then fails one of the sufficient conditions (/biology lab is a class) instead of failing the necessary condition.

Mismatched conclusion. The stimulus concludes that either one of the two sufficient conditions must have failed; (B) concludes that both of the sufficient conditions must have failed (that not all medical research is significant AND this research is not medical).

The argument structure for (C) matches the structure of the stimulus:

Mismatched conclusion. The stimulus concludes that either one of the two sufficient conditions must have failed; (D) concludes by specifying which of the two sufficient conditions must have failed (/clinical psychology is a science). The stimulus does not specify which of the two sufficient conditions must have failed, so (D) does not match the structure of the stimulus.

Mismatched premises. The stimulus gives a conditional relationship with two sufficient conditions in conjunction; (E) gives a conditional relationship with one sufficient condition (all classes are canceled today) and two necessary conditions (today is a holiday and the library is closed).