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.
Q: Prompt: John studies for his math test. He 
Completion A: watches a cat video. 
Completion B: work on algebra problems. 
Completion C: opens his English textbook. 
Completion D: reads the newspaper.
A: 
Completion B