Sandy could do nothing but

Sandy could do nothing but ____ to his mother that he was wrong.A.admitting B.admits C.admit D.
Sandy could do nothing but ____ to his mother that he was wrong.
A.admitting B.admits C.admit D.to admit 为什么选C 句子后面的that 引导的是什么从句呀?

do nothing but 后接省略to的不定式,故用C.that 从句是admit的宾语从句
再问： 翻译下
再答： sandy 别无选择，只得向他妈妈承认自己错了。
再问： 会不会是but 连接两个并列句 admit to 做主语 ？ admit to 可以做主语吗？
再答： 它是动词，不可能做主语，只能带宾语
再问： 或祈使句 ？ admit to 可以做祈使句开头么 ？
再答： 不可以，祈使句是省略了主语you 的句子