The graph of f(x) = 4x3 – 13x2 + 9x + 2 is shown below. On a coordinate plane, a function is shown. The function starts from the bottom of quadrant 3 and goes up through the x-axis at (0, negative 0.25) and then through the y-axis at (0, 2). It then starts to curve down at (0.5, 4) until it reaches (1.75, negative 0.5). It then curves up and crosses the x-axis at (2, 0) and goes up approaching x = 3. How many roots of f(x) are rational numbers