如果题目是在提问的话,严格说来这题没正确答案.
要选对"What are you doing these days"的回答的话,依题只能选C; 如果要选对问句的补充,可以选A.
例如:
场景一:A:What are you doing these days?B:I am doing my homework.
场景二:What are you doing these days?Are you doing your homework?