Suppose f(x) is a function such that if p < q, f(p) < f(q). Which statement best describes f(x)?

The condition says f is strictly increasing: whenever p < q, f(p) < f(q). An odd function can satisfy this; for example, f(x) = x is strictly increasing and odd. An even function cannot be strictly increasing on a domain containing both x and −x for some positive x, because evenness gives f(−x) = f(x), but strict increase requires f(−x) < f(x). So the best choice is “f(x) can be odd but cannot be even.”

AI-written and checked against the verified answer.