Data Sufficiency

So the Princeton Review says that if the answer to a data sufficiency can be found to be EITHER always YES or always NO, then the data is sufficient. This makes sense. HOWEVER, I am doing the Mcgraw-Hill Conquering Math book (2006 ed.) and for some of the questions, even when the answer is ALWAYS NO, it still says the correct answer is E (neither statements are sufficient). So I am wondering what will be correct on the actual GMAT?

As an example, this is Question 12:

Is the whole number N divisible by 3 or more positive integers?
1) N is a prime number
2) 0 < N < 4

1) This statement says N is a prime number, therefore N can only be divisible by 2 integers, 1 and itself. Thus, if N is a prime number, it is NEVER divisible by 3 or more integers and the answer is ALWAYS NO. Therefore, this statement is SUFFICIENT.

2). This statement says that N can be 1, 2, or 3. No matter which it is, N is not ever divisible by 3 or more positive integers. Again, the answer is always NO, that N is not divisible by 3 or more positive integers. Thus, this statement is also SUFFICIENT.

So... I thought the correct answer to this would be D. However, the book says that it is E... WHY?? This is confusing me as to how I should answer on the real test!!!