The correct option is A 1245
We know that if a number is divisible by 3 and 5, then the number is also divisible by 15.
Sum of digits in 1245=1+2+4+5=12 is a multiple of 3 so, 1245 is divisible by 3.
Last digit of the number is 5 hence, 1245 is also divisible by 5.
Since 1245 is divisible by both 3 and 5, the number is also divisible by 15.