The function f(x) is shown on the graph. On a coordinate plane, a curved line with 3 arcs, labeled f of x, crosses the x-axis at (negative 2, 0), (1, 0), and (3, 0), and the y-axis at (0, negative 6).

If f(x) = 0, what is x?

0 only
–6 only
–2, 1, or 3 only
–6, –2, 1, or 3 only