General Studies · Number Analogy

Given below are two sets of numbers. In each set of numbers, a certain mathematical operation on the first number results in the second number. Which of the options follows the same operation as given in the question? (NOTE: Operations should be performed on the whole number, without breaking down the numbers into its constituent digits. E.g. 13 - Operations on 13 such as adding/subtracting/multiplying etc. to 13 can be performed. Breaking down 13 into 1 and 3 and then performing mathematical operations on 1 and 3 is not allowed.) (21, 10) (87, 43)