N____ of then failed the math exam,they all passed it.

N____ of then failed the math exam,they all passed it.
N____ of then failed the math exam,they all passed it.

N____ of then failed the math exam,they all passed it.
None
none of都不,都没有
then应该是them吧
他们中没有人在数学考试中失败,他们都过了.

填入one意思是没一个人在英语考试中失利