2／5,3／7,4／10,6／14,8／20,12／28,（) A.224／56B.14／32C.20／48D.16／40

2/5, 3/7, 4/10, 6/14, 8/20, 12/28, ()

A.224/56

B.14/32

C.20/48

D.16/40

请帮忙给出正确答案和分析，谢谢！