Which of the following equations represents a parabola with a horizontal axis of symmetry, vertex at (−6, 11), and p = 5? (2 points) a (x − 11) 2 = 20(y + 6) b (x + 11) 2 = −20(y − 6) c (y − 11) 2 = 20(x + 6) d (y + 11) 2 = −20(x − 6)