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: A sad lady was waiting at her home for her son to come. Her son
Completion A: was taking extra classes
Completion B: did not have legs to walk home
Completion C: was eating dog biscuits
Completion D: was running late for the president
A:
Completion A