General Intelligence · Number Analogy

13 is related to 103 following a certain logic. Following the same logic, 9 is related to 71. To which of the following is 15 related, following the same logic? (NOTE: Operations should be performed on the whole numbers, 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.)