— are you?—I’m twelve.A. How B. How old C. What

问题补充：

— are you?

—I’m twelve.

A. How B. How old C. What

答案：

解析：根据答语我们知道，问句应该是问年龄的。How old are you？是问“你多大了？”；而How are you？是问“你好吗?”；What are you ？是问“你是干什么的？”。所以本题选B。