(a) Describe the set of points whose distance from the x-axis equals the distance from the yz-plane.
A. A cylinder opening along the z-axis
B. A cone opening along the x-axis
C. A cone opening along the z-axis
D. A cone opening along the y-axis
E. A cylinder opening along the x-axis
F. A cylinder opening along the y-axis
(b) Find the equation for the set of points whose distance from the x-axis equals the distance from the yz-plane.
A. x^2 + z^2 = r^2
B. y^2 = x^2 + z^2
C. y^2 + z^2 = r^2
D. x^2 = y^2 + z^2
E. z^2 = x^2 + y^2
F. x^2 + y^2 = r^2