从所给出的单词中选出合适的选项完成对话。

A: What are you doing, Ben?

B: I'm a book.

A: What is the book about?

B: It's about animals. These animals are in

A: What are they?

B: They're pandas, South China tigers and blue whales.

A: How many are there in the wild?

B: There are only one thousand six hundred pandas in the wild.

A: How about blue whales?

B: There are about ten thousand in the wild.