My friend offered to pay my plan

My friend offered to pay my plane fare, which was very ________ of him.
A、mean
B、general
C、generous
D、gentle
【正确答案】：C
【题目解析】：generous大方的，慷慨的。句意：我的朋友主动提出帮我付机票钱，他真是太慷慨了。