How long haven't we seen each other?

How long haven't we seen each other?
Well,it _____ nearly two years since we ____ last.
A.is/have met B.was/had met C.is/met D.has been/had met
They asked me to have a drink with them.I said that it was 10 years since I _____ good drink.
A.had enjoyed B.was enjoying C.enjoyed D.had been enjoying
请问这两个题各自选哪个?有什么区别?请详细一些.