In each of the following questions, select the related letter/word/number from the given alternatives :
8:56 :: 9 : ?

Options

A. 90
B. 73
C. 72
D. 89

Answer

C

Explanation

`8 xx ( 8- 1) = 56`
`9 xx ( 9 - 1) = 72`
Alternatively , `(2)^(2) = 8 , (3)^(2) = 9`
`(8)^(2) - 8 = 56 , (9)^(2) = 72`