People who drink wine _ to drive .为什么不能用isn't allowed

问题描述:

People who drink wine _ to drive .为什么不能用isn't allowed
People who drink wine _ to drive .
B.isn't allowed
D.mustn't be allowed
【答案是D,我想知道B为什么错了,难道是因为“be allowed to”结构中的be不能够与is are什么的互相转换吗?求学霸解答十分感谢(。・ω・。)ノ♡√】

因为people是复数B.isn't allowed 是单数,主谓不一致