What is the equation of the circle with center (0, 0) and radius 4?
Correct: A
The general equation of a circle with center (h, k) and radius r is (x - h)^2 + (y - k)^2 = r^2. In this case, the center is (0, 0) and the radius is 4. Substituting these values into the equation gives (x - 0)^2 + (y - 0)^2 = 4^2, which simplifies to x^2 + y^2 = 16.