Group the given figures into three classes using each figure only once.
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
Correct answer is B
1, 5, 6 have two similar elements, one inside the other.
2, 3, 4 contain straight lines each dividing, the figure into two equal parts.
7, 8, 9 have one element placed inside a different element.