In the following question, the second number is related to the first number in some way, choose the alternative which is similarly related to the third number 13 : 196 : : 15 : ?

221 247 298 256

256

THE LOGIC FOLLOWED HERE IS : ( IST NUMBER +1 )2 = iiND NUMBER AS 13 : 196 ( 13  + 1 ) 2 = 142 = 196 SIMILARLY 15 : ? ( 15  + 1 ) 2 = 162 = 256