It’s your efforts that have made your stay so ________(富有成效的)

But it's your efforts ....... that have made your stay so fruitful.

A、who
B、what
C、which
D、that

But it’s your efforts that have made your stay so fruitful.

What's the ______ of your stay?

Your help has made my stay here ....... and successful.

A、pleasure
B、pleasant
C、pleasing
D、pleased