▲完全可以的。你去看看历年高考英语题就清楚了。

比如《2016年普通高等学校招生全国统一考试•课标乙卷》的第20题（听力题）：

20. Why are engineering graduates more likely to accept a job?

A. They need more work experience.

B. The salary is usually good.

C. Their choice is limited.

再如《2016年普通高等学校招生全国统一考试•课标乙卷》的第25题（阅读理解B）：

25. Why was Garza’s move a success?

A. It strengthened her family ties.

B. It improved her living conditions.

C. It enabled her to make more friends.

D. It helped her know more new places.

以上两句的回答选项都没有用because。

▲当然用 because 来回答也完全可以。

比如下面一题，摘自2013年普通高等学校招生全国统一考试•浙江卷》的第47题（阅读理解B）：

47. Why do some old people look a little shrunken as they age?

A. Because their spine is in active use.

B. Because they are more easily affected by gravity.

C. Because they keep growing backwards.

D. Because their spine becomes more bent.

▲除以上情况外，也可根据需要有其他的回答方式（如不定式、介词短语等），如以下两例也摘自高考英语试题：

1. Why are the speakers making the trip?

A. For business.        B. For shopping.        C. For holiday.

2. Why does the man talk to Dr. Simpson?

A. To make an apology.

B. To ask for help.

C. To discuss his studies.