What is the equation of a circle with center (1,-4) and radius 2?
O
A. (x-1)2 + (y + 4) = 4
B. (x-1) - (y + 4)2 - 4
O C. (x+1)2 + (y - 4)2 - 4
D. (x - 1)2 + (y + 4)2 - 2