Who ▁the paper in the world?Cai Lun▁.A invented;did B was invented;was C did invent;was

问题描述:

Who ▁the paper in the world?Cai Lun▁.A invented;did B was invented;was C did invent;was

选A.
意思:谁发明了世界上的纸?蔡伦发明了(世界上的纸).
did代invented,后省略了the paper in the world.