Study the given pattern carefully and select the number that can replace the question mark (?) in it.
First row: 15, 3, 252
Second row: 11, 5, 246
Third row: 9, 6, ?
(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)