If f(x) is an odd function and the graph of f(x) includes points in quadrant iv, which statement about the graph of f(x) must be true?

Definition: The function f(x) is odd, when f(-x)=f(x) for all x. 
If f(x) is an odd function and the graph of f(x) includes points in quadrant IV, then for these points .
When you substitude -x instead of x (-x becomes non-positive), then f(-x) becomes -f(x) and since f(x) is non-positive, then -f(x) is non-negative. Points that have x non-positive and y non-negative lie in the II quadrant.
Conclusion: the graph of f(x) must include points in quadrants II and IV.

Odd fucnction ⇒ f(x) = f(-x)

The fourth quadrant ⇒ positive x, negative y

Then, the function has points with negative x, negative y. This means that the graph include points in the third quadrant.