—What a nice watch!—My grandpa gave it to me as a gift on my birthday. A. nineB. ninth C.

问题补充：

—What a nice watch!

—My grandpa gave it to me as a gift on my birthday.

A. nine

B. ninth

C. the ninth

D. a ninth

答案：

A. nine

(答案→)B. ninth

C. the ninth

D. a ninth

解析：句意：多漂亮的手表！我爷爷送给我的十岁生日礼物。Birthday是单数名词，前面有my修饰，所以选B。