Group the given figures into three classes using each figure only once.
A1,3,9; 2,5,6; 4,7,8
B1,3,9; 2,7,8; 4,5,6
C1,2,4; 3,5,7; 6,8,9
D1,3,6; 2,4,8; 5,7,9
Correct answer is A . I clicked 'a' and rechecked 2 times.....yet when I clicked submit they said I clicked 'd' and that I got it wrong