Direction In each of the following questions, group the given figures into three classes using each figure only once. -
21.

 A. 1,7,9 ; 2,3,6 ; 4,5,8 B. 1,2,9 ; 3,4,6 ; 5,7,8 C. 1,6,8 ; 2,4,7 ; 3,5,9 D. 1,7,8 ; 2,9,3 ; 6,4,5
Answer: Option A
Explanation:

1, 7, 9 contain two similar elements one inside the other but not touching each other.

2, 3, 6 contain two similar elements one inside the other and both touching each other.

4, 5, 8 are divided into equal parts by straight lines emerging from the centre.

22.

 A. 1,4,7 ; 2,5,9 ; 3,8,6 B. 2,6,9 ; 1,4,7 ; 5,8,3 C. 1,4,7 ; 2,3,6 ; 5,8,9 D. 3,5,1 ; 4,7,8 ; 6,2,9
Answer: Option C
Explanation:

5, 8, 9 are objects having both base as well as upper lid.

2, 3, 6 are objects having base but not upper lid.

1, 4, 7 tare objects which have neither a base nor an upper lid attached to them.

23.

 A. 1,5,8 ; 2,6,7 ; 3,4,9 B. 1,5,7 ; 2,6,8 ; 3,4,5 C. 1,5,8 ; 2,4,7 ; 3,6,9 D. 1,5,8 ; 2,6,9 ; 3,4,7
Answer: Option C
Explanation:

3, 6, 9 are geometrical figures containing line segments (the number of these line segments is half the number of sides in the figure) parallel to the sides of the figure.

1, 5, 8 consist of a circle and a triangle intersecting it. The triangle is also divided into two equal parts by a straight line.

2, 4, 7 are all funnel shaped figures.