Cowan was the last man ______, voluntarily covering the withdra

Cowan was the last man ______, voluntarily covering the withdrawal of his remaining comrades.
A、 to leave
B、 leaving
C、 left
D、 to have left
【正确答案】：A
【题目解析】：该题考查的是不定式做定语，当名词前面有序数词修饰时，用不定式做后置定语，选项A为正确答案。