Describe the graph of 9x2 - y2 + 16z2 = 144.
◦ a hyperboloid of one sheet
◦ a hyperboloid of two sheets
◦ a hyperbolic paraboloid
◦ an elliptic paraboloid
◦ an ellipsoid (or a sphere)
◦ a cylinder (circular, elliptic, parabolic, or hyperbolic)
◦ a cone (circular, elliptic, parabolic, or hyperbolic)
◦ none of the above