Can he come at ten? I know it's inconvenient for him, ______I mu

Can he come at ten? I know it's inconvenient for him, ______I must see him.
A、and
B、or
C、for
D、but
【正确答案】：D
【题目解析】：But并列连词，表转折和对比关系，意为“可是；但是；然而”。