The Surface Area of the Surface Cut From $x ^ { 2 } + y ^ { 2 } = 9$

Multiple Choice

The surface area of the surface cut from $x ^ { 2 } + y ^ { 2 } = 9$ by z = x is

A) $6 \sqrt { 8 }$
B) $2 \sqrt { 6 }$
C) $\sqrt { 6 }$
D) 18
E) 9