Group the given figures into three classes using each figure only once.
A.
1,5,8 ; 3,4,7 ; 2,6,9
B.
1,3,6 ; 4,5,9 ; 2,7,8
C.
1,3,6 ; 2,5,7 ; 4,8,9
D.
6,7,8 ; 1,3,7 ; 2,4,9
Correct answer is C
1, 3, 6 contain one complete circle each.
2, 5, 7 contain a semi-circle each.
4, 8, 9 contain a triangle each.