**Concept: The question tests on fundamentals of Coordinate Geometry**

**Solution:**

x - y > 0, then x > y

In Quadrant I where x is positive and y is positive. Both situations are possible where x > y and y > x

In Quadrant II where x is negative and y is positive, x can never be greater than y.

In Quadrant III where x is negative and y is negative. Both situations are possible where x > y and y > x

In Quadrant IV where x is positive and y is negative, x is always greater than y.**Option C**