－How long has your grandpa ?－For about 3 months. A. died B. been diedC. been deadD. death

问题补充：

－How long has your grandpa ?

－For about 3 months.

A. died

B. been died

C. been dead

D. death

答案：

A. died

B. been died

(答案→)C. been dead

D. death

解析：句意：你的爷爷死了多久了？——已经大约三个月了。结合语境可知上文描述的是持续性的状态，选项A表示瞬间动作，选项B中die不能用作被动语态，选项D名词，不能用作谓语动词。故选C。