Hey gmatruler,
The question asks whether k is a power of 2, a number such as {2, 4, 8, 16...}
(1) if k = 2^6 then it will be a power of 2. However, k could be 2^6 * 13, which is not a power of 2. NOT SUFFICIENT.
(2) k has no odd factor (all factors break down to prime factors), so 2 must be the only prime factor of k (remember that k>1). SUFFICIENT
The answer is B. A more detailed solution as well as a step-by-step video solution is available at
GMATPrep Question 1065. To practice similar questions, set topic='Number Properties' and difficulty='700+' in the Drill Engine.
-Patrick
