I lived with my sister this summer and didn’t have to pay rent. So I _____ save most of my salary.

A．could

B．would

C．was able to

D．should

下列哪一社会关系属于法律关系

A．未经国家认可的收养关系

B．五线谱合唱团内部的团长与团员关系

C．家长老孔与其未成年子女小孔的监护关系

D．老金与小孙的忘年交关系