Gmat prep DS please help!!

My answer is A.

What is the OA?

Since the symbol represents either multiplication or addition, we can test both 1) and 2) with these functions. Also, it's important to note that K is an integer (i.e. a whole number and not a fraction).

1) 2 (+ or X) K = 3
2 + 1 = 3
K= 1
Only a fraction multiplied by 2 (i.e. 3/2) will satisfy this statement, as 2 X 3/2 = 3. However, since K is an integer then we can cancel out the multiplication and have a definite answer when using addition.

A is correct.

2) 1 (+ or X) 0 = K
1 + 0 = 1, K = 1
1 x 0 = 0, K = 0
There are two different answers for K and therefore insufficient. There's no need to combine both answers since A is sufficient on its own.

Please let me know what the OA is. Also, I'm sure there are other ways to answer this question and I look forward to other people's respsonses.

Nervermind..I just realized you posted the OA.. A is correct.