A.What do you do?

B.What are you do?

C.What are you doing?

【答案】C

【解析】

A. What do you do?你是什么职业？B. What are you do?句子错误，are后不能跟动词原形；C. What are you doing?你正在做什么？题目要求问别人正在干什么，故选C。