Match the surfaces with the appropriate descriptions.

 1. $z = x^{2}$
 2. $z = y^{2} - 2x^{2}$
 3. $z = 2x + 3y$
 4. $z = 2x^{2} + 3y^{2}$
 5. $x^{2} + 2y^{2} + 3z^{2} = 1$
 6. $x^{2} + y^{2} = 5$
 7. $z = 4$

A. hyperbolic paraboloid
B. horizontal plane
C. circular cylinder
D. ellipsoid
E. elliptic paraboloid
F. parabolic cylinder
G. nonhorizontal plane