The circle below is centered at (3, 1) and has a radius of 2. What is its
equation?
O A. (x-3)2 + (y - 1)2 = 4
O B. (x-1)2 + (x-3)2 = 2
O c. (x - 1)2 + (y - 3)2 = 4
O D. (x-3)2 + (x-1)2 = 2