The Indefinite Integral $\int \sec ^ { 2 } ( 6 x ) d x$

Multiple Choice

The indefinite integral $\int \sec ^ { 2 } ( 6 x ) d x$ is

A) $12 \sec ( 6 x ) \tan ( 6 x ) + C$
B) $\frac { \tan ( 6 x ) } { 6 } + C$
C) $\frac { \sec ^ { 3 } ( 6 x ) } { 18 } + C$
D) $\frac { \sec ^ { 3 } ( 6 x ) } { 6 } + C$
E) $\frac { \tan ^ { 2 } ( 6 x ) } { 6 } + C$