In three of the following four number pairs, the numbers are related in the same way and thus form a group. Which number pair DOES NOT belong to that group?
(NOTE: Operations should be performed on the whole numbers, without breaking down the numbers into their constituent digits. E.g. 13 – Operations on 13 such as adding / subtracting /multiplying to 13 can be performed. Breaking down 13 into 1 and 3 and then performing mathematical operations on 1 and 3 is not allowed.)

From the given options - 

Logic: the second number is divisible by the first:
30 ÷ 5 = 6
110 ÷ 10 = 11 
70 ÷ 8 = 8.75 
12 ÷ 3 = 4 
Option (C): 8 : 70 is the odd one out because 70 is not divisible by 8, while in all other pairs, the second number is divisible by the first.

Correct answer is (c) 8 : 70