In the following number-pairs, the second number is obtained by applying certain mathematical operations to the firstnumber. Select the set in which the numbers are related in the same way as are the numbers of the following sets.

(NOTE: Operations should be performed on the whole numbers, without breaking down the numbers into its constituentdigits. E.g. 13 – Operations on 13 such as adding/subtracting/multiplying etc. to 13 can be performed. Breaking down 13 into1 and 3 and then performing mathematical operations on 1 and 3 is not allowed.)

10 , 99

21, 440

10 → 99

21 → 440

Logic: The square of 1st number - 1 = 2nd number.

10²-1 = 100 - 1 = 99

21²- 1 = 441 - 1 = 440

30²- 1 = 900 - 1 = 899 (Follow)

3²- 1 = 9 - 1 = 8 (Not follow)

26²- 1 = 676 - 1 = 675 (Not follow)​

15²- 1 = 225 - 1 = 224(Not follow)​