Which graph represents the equation y2 = –4x? On a coordinate plane, a parabola opens to the left. It has a vertex at (0, 0), a focus at (negative 1, 0), and a directrix at x = 1. On a coordinate plane, a parabola opens down. It has a vertex at (0, 0), a focus at (0, negative 1), and a directrix at y = 1. On a coordinate plane, a parabola opens to the left. It has a vertex at (0, 0), a focus at (negative 4, 0), and a directrix at x = 4. On a coordinate plane, a parabola opens down. It has a vertex at (0, 0), a focus at (0, negative 4), and a directrix at y = 4.