A circle has a diameter of 12 units, and its center lies on the x-axis. What could be the equation of the circle? Check all that apply.

(x – 12)2 + y2 = 12
(x – 6)² + y² = 36
x² + y² = 12
x² + y² = 144
(x + 6)² + y² = 36
(x + 12)² + y² = 144