which equation is the equation of a 10 cm radius circle with its center at (3, -6)?

a. (x - 3)² + (y + 6)² = 100
b. (x - 3)² + (y + 6)² = 20
c. (x + 3)² + (y - 6)² = 20
d. (x + 3)² + (y - 6)² = 100