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Group the given figures into three classes on the basis of their identical properties by using each figure only once.                                                                                                                                                                             (SOF IMO 2017)  

A) 1, 2, 3; 4, 5, 8; 6, 7, 9               

B) 1, 5, 6; 2, 3, 4; 7, 8, 9

C) 1, 3, 5; 2, 4, 8; 6, 7, 9                   

D) 1, 4, 7; 2, 5, 8; 3, 6, 9