1.  Choose the odd numeral pair/group in each of the following questions :

A. 5, 10, 20, 15
B. 10, 20, 40, 30
C. 10, 20, 60, 45
D. 15, 30, 60, 45

Answer: Option C

Explanation:

In all other groups, the numbers are in the ratio 1 :2 : 4 : 3.