白勇的一道题,哪位帮忙解释一下,谢谢

Archaeologists in Ireland believe that a recently discovered chalice, which dates from 8th century, was probably buried to keep from being stolen by invaders.

a) To keep from

b)To keep it from

c)To avoid

d) in order that it would avoid

e) in order to keep from

答案是B, 但我觉得这个it放在这里是有问题的, 哪位可以帮助解释一下吗? 谢谢!

为什么会觉得有问题?it指代chalice,如果没有it就不知道是keep什么from being stolen

谢谢,这个明白,但这个it不可以省略吗?  我本来觉的Avoid be doing 好象蛮顺的嘛...

没有it 才是不对的，应该没有限定的动作的对象，存在歧义啊！

以下为OG183的解释：

In choice A, the phrase/row being stolen lacks the necessary noun or pronoun that specifies what it is that might be stolen. Choice B is best because it provides the pronoun it, which refers to chalice. Like choice A, choices C and E lack the pronoun. D is wordy and awkward in its use of the passive voice. Moreover, avoid is used imprecisely in C and D because it illogically suggests that the chalice is acting to prevent its own theft.