A circle in the xy -plane has a diameter with endpoints at (0,3) and (-4,0). Which of the following is an equation of the circle?

a. (x - 3/2)² + (y + 2)² = 25/2
b. (x + 4)² + (y - 3)² = 5/4
c. (x + 2)² + (y - 3/2)² = 5/2
d. (x + 2)² + (y - 3/2)² = 25/4