Hi vaibhav101,

We're told that M and N are nonzero integers. We're asked if M/N is an integer. This is a YES/NO question and we can answer it with a mix of TESTing VALUES and logic.

1) 2M is divisible by N

IF....
M=1 and N=1, then the answer to the question is YES.
M=1 and N=2, then the answer to the question is NO.
Fact 1 is INSUFFICIENT.

2) M is divisible by 2N

M=2 and N=1, then the answer to the question is YES.
M=4 and N=1 or N=2, then the answer to the question is YES either way.
You should notice that since M is divisible by 2N, then M/2N will ALWAYS be an integer. By extension, if we replace "2N" with "N", then that integer will DOUBLE (and we'll still have an integer. Thus, M/N will ALWAYS be an integer and the answer to the question is ALWAYS YES.
Fact 2 is SUFFICIENT.

Final Answer: B

GMAT assassins aren't born, they're made,
Rich