Write the equation of the circle with center (2, -3) and a radius of 4.
A) (x + 2)^2 + (y - 3)^2 = 4
B) (x - 2)^2 + (y + 3)^2 = 4
C) (x + 2)^2 + (y - 3)^2 = 16
D) (x - 2)^2 + (y + 3)^2 = 16