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: He is the smartest person in the class. He 
Completion A: knows how to open a door 
Completion B: is easygoing 
Completion C: could answer the question in the course 
Completion D: always get angry
A: 
Completion C