$\text { Find the indefinite integral by making the substitution } x = 6 \sec \theta \text {. }$

Multiple Choice

$\text { Find the indefinite integral by making the substitution } x = 6 \sec \theta \text {. }$ $$\int \frac { 1 } { \sqrt { x ^ { 2 } - 36 } } d x$$

A) $\ln \left| \sqrt { x ^ { 2 } + 36 } \right| + x ^ { 2 } + C$
B) $\ln \left| \sqrt { x ^ { 2 } - 36 } \right| + C$
C) $\ln \left| x \sqrt { x ^ { 2 } - 36 } \right| + C$
D) $\ln \left| \sqrt { x ^ { 2 } - 36 } + x \right| + C$
E) $\ln \left| x \sqrt { x ^ { 2 } - 36 } \right| + x + C$