The correct answer is C

Explanation

All numbers divisible by both  and  are the multiples of  and . Since  and  have no prime factor in common , then the least common multiple of  and  is equal to their product, namely . Every other multiple of  and  is divisible by . Thus, if  is divisible by a number then all the multiples of  and  are divisible by that number. Therefore, it is enough to check by which number in the given options is  divisible. Only  divides  and none of the other do. The answer must be .