1.  Which one will replace the question mark ?

A. 64
B. 144
C. 169
D. 25

Answer: Option A

Explanation:

The numbers are squared in ascending order

In first circle,

(3)2 = 9

(4)2 = 16

(5)2 = 25

(6)2 = 36.

In second circle,

(4)2 = 16

(5)2 = 25

(6)2 = 36

(7)2 = 49.

In third circle,

(6)2 = 36

(7)2 = 49

(8)2 = 64

(9)2 = 81.