Hi imran556691,
This prompt has 2 correct answers. Is it meant to be a GMAT question or a general 'concept' question?
We're told that 2N is a MULTIPLE of 7, so 2N could be 0, 7, 14, 21, 28, 35.....
By extension, N could be 0, 3.5, 7, 10.5, 14, 17.5....
Since we don't know WHICH multiple of 7 we're dealing with, we have to consider a few possibilities to see if a pattern occurs...
IF N = 0, then all of the answers are multiples of 7.
IF N = 3.5, then Answers A and D are multiples of 7.
IF N = 7, then A, B and D are multiples of 7.
IF N = 10.5, then A and D are multiples of 7.
Based on the above examples, only Answers A and D will ALWAYS be a multiple of 7.
GMAT assassins aren't born, they're made,
Rich
