You will be given a definition of a task first, then some input of the task.
Given a prompt and four completions, select the completion that is the most plausible in continuing or answering the prompt. This task is designed to test common sense and has various categories ranging between idioms, negated statements, polysemy, subject referencing, and quantitative reasoning. Generate either Completion A, Completion B, Completion C, or Completion D.

Prompt: After scoring poorly on multiple exams, Harper wondered 
Completion A: what the weather was like. 
Completion B: if he would be the top student in class. 
Completion C: if chicken wings were on sale at the supermarket. 
Completion D: whether he understood the material.
Output:
Completion D