3. The graph of y = f '(x), the derivative of f(x), is shown below. List the intervals where the graph of f is concave up.

Graph consists of 3 line segments from x equals negative 4 to x equals 4. Graph is decreasing from x equals negative 4 to x equals negative 2, increases from x equals negative 2 to x equals 2 and decreases from x equals 2 to x equals 4. There are x intercepts at x equals negative 4, 0 and 4. (5 points)
(-4, -2) U (2, 4)
(-2, 2)
(-4, 0)
(0, 4)