Use each of the following figures only once to form three groups. The three groups thus formed are:

A

(1,7), (2,5,4), (6,3)

B

(1,3), (2,5,4), (6,7)

C

(1,3), (2,6,4), (5,7)

D

(7,3), (2,5,4), (6,1)