这句是keep off还是prevent from?

问题描述:

这句是keep off还是prevent from?
Pigs are usually in dirty water or mud.Mud can( )insects( )them.
A keep ...from
B protect ...from
C keep ...off
D prevent ,from

C.把昆虫赶走.
D是指保护某人不受.侵害.eg.
Doing exercise prevents me from obesity.
如果用这个,就成了污泥保护昆虫不受猪的侵害了.