Answer:
4
Explanation:
There are only 2 inputs, X and Y, and the number of different input configurations will be 2-to-the-power-of the number of inputs.
2² = 4
In other words, XY can be 00,01,10 or 11 and that's it. Four combinations.
BTW, (x AND Y) OR (NOT x AND NOT y) is allso called XNOR. See picture.
