Find the missing number?

A. 56

B. 47

C. 51

D. 63

Answer: Option A

Solution(By Examveda Team)

In each diagram, multiply the left hand number by the upper central number to give the central number one line down, and multiply the right hand number by the upper central number to give the lower central number. So,

7 * 3 = 21.
7 * 8 = 56.