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.

Let me give you an example: Prompt: A clown is fashioning animals from long balloons. He 
Completion A: releases the animals into their natural habitat. 
Completion B: makes a giraffe and hands it to a child. 
Completion C: yells out for his second in command to pilot the battleship around the obstacle. 
Completion D: releases the balloon and it flies high into the air.
The answer to this example can be: Completion B
Here is why: The clown is an entertainer and is twisting balloons to resemble an animal. There are no live animals, and these types of twistable balloons are not able to fly or float up.

OK. solve this:
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
Answer:
Completion A