Find the equation of the circle if the endpoints of the circle's diameter are (2,-7) and (-6,1). a. (x + 6)^2 + (y - 1)^2 = 32 b. (x + 2)^2 + (y + 4)^2 = 25 c. (x + 2)^2 + (y + 3)^2 = 32 d. (x + 2)^2 + (y + 3)^2 = 16