Explanation

In this question, we will eliminate any answer choice that we can demonstrate must be divisible by 3. And if we find an example in which any answer choice isn't divisible by three, that one is the correct answer. (B) has 3 as a factor, so it's divisible by 3 and is not the answer. There is a pattern in the other answer choices: they are variations on the theme that if you take any three consecutive integers, one of them will have to be divisible by three. In 3, 4, 5, it's 3; in 4, 5, 6, it's 6; in 5, 6, 7, it's 6. That way, if you multiply the three numbers, one will bring a factor of 3 into the final product. (A) seems to stand out because k and k+3 are redundant in this respect. We can try a number. Say k=5. Then . That's not divisible by 3.

The correct answer is (A).