—?—I’m twelve years old. A. How are you B. What’s your name C. How old are you

问题补充：

—?

—I’m twelve years old.

A. How are you B. What’s your name C. How old are you

答案：

解析：本题回答语回答的是年龄，对年龄提问的用how old，故本题选C。