The correct option is (A): 37. 2412 = (23 x 3)12 = 236 x 312 1816 = (2 x 32)16 = 216 x 332 3618 = (22 x 32)18 = 236 x 336 The power of 2 in a can be any value from 0 to 36 because the LCM has 236 which is already present in 2412. So, a may or may not contain powers of 2. Thus, there are 37 possible cases.