The gray building is where the workers live, and the white one i

The gray building is where the workers live, and the white one is where the spare parts___________.
A、are produced
B、are producing
C、produced
D、being produced
【正确答案】：A
【题目解析】：句意：灰色的大楼是工人们居住的地方，而白色的大楼是零件被生产的地方。