C肯定是不能选的.from后面跟的一般是地点或在表示"从xx中找出xx"时指前面的那些物品.
根据longman的解释
介词in有这么一种用法.
used to say what person or thing has the quality you are mentioning:
There was a hint of spring in the air.
I don't think Freddy had it in him to be a killer.
She's everything I'd want in a wife (=she has every quality I would
want a wife to have).
所以这里应该是in.
debt有两种情况,一种是可数的,一种是不可数的...
老师如果告诉你debt是不可数的,那么他绝对是错了.
当debt做不可数名词的时候表示的是"我们欠别人的钱"
有in debt (to somebody),get/run/fall etc into debt,be heavily/deeply in debt
做可数名词的时候表示的是"欠别人一笔钱"
有debt of,pay (off)/repay/clear/settle etc a debt,run up/amass debts这几种用法.
所以当用in debt to somebody时,debt不能加s.此时debt是不可数名词.
returnee这个词是可数名词,加不加s和一般名词的复数用法没差别...