The vertex of a parabola is (6,2), and the equation of its directrix is y = 0. What is the equation of this parabola in standard form?
a) (x-6)² = -8(y-2)
b) (x-6)² = 8(y-2)
c) (y-2)² = -8(x-6)
d) (y-2)² = 8(x-6)