---Excuse me ,Is this seat taken?---_________,the man got his book and left a few minutes ago .

问题描述:

---Excuse me ,Is this seat taken?---_________,the man got his book and left a few minutes ago .
A,I am afaid so B.I don't think so C.I don't know D.I hope so

我觉得应该选C,但如果没有选项的话,我选I'm not sure.