Evaluate the Integral $\int \tanh \left( \frac { x } { 2 } \right) d x$

Multiple Choice

Evaluate the integral.
- $\int \tanh \left( \frac { x } { 2 } \right) d x$

A) $2 \operatorname { sech } ^ { 2 } \frac { x } { 2 } + C$
B) $2 \ln \left( \sinh \frac { x } { 2 } \right) + C$
C) $\ln \left( \operatorname { coth } \frac { x } { 2 } \right) + C$
D) $2 \ln \left( \cosh \frac { x } { 2 } \right) + C$