根据对话内容从方框中选择能填入空白处的最佳选项补全对话

A: Hi, Dave!

B: I' m looking up some information about Asian elephants.

A: Really？

B: They can live for about sixty years.

A:

.B: Grass, leaves and fruit.

A: Where do they live?

B:  But now some of them don't have safe places to live.

A: Why not?

B: Because people are cutting down forests and killing them for their ivory (象牙).

A:

B: Stop people cutting down forests and killing them.

A: I see.

A. What are you doing? B. How long can they live? C. What do they usually eat? D. What can we do to help them? E. In the forests of South-east Asia.