请问一下。

Q14:

A scrub jay can remember when it cached a particular piece of food in a particular place, researchers have discovered, and tend not to bother to recover a perishable treat if stored long enough to have rotted.

1. tend not to bother to recover a perishable treat if
2. they tend not to bother recovering a perishable treat
3. tending not to bother to recover a perishable treat it
4. tends not to bother recovering a perishable treat
5. tends not bothering to recover a perishable treat it

答案是D，怎么也想不明白

基本结构：

A jay can remember, and tends not to

A, tend应该为tends

B, they无指代

C, and tendin, tending和谁并列呢？

E, tend to do而不是tend doing

你觉得D有什么疑问吗？

为什么不能是 jay can remember, and (can)tend not to ?

是情态动词不能被省略吗？