Let $f ( x ) = \cosh \left( x ^ { 2 } + 1 \right)$

Multiple Choice

Let $f ( x ) = \cosh \left( x ^ { 2 } + 1 \right)$ Then $f ^ { \prime } ( x )$ is

A) $- 2 x \sinh \left( x ^ { 2 } + 1 \right)$
B) $2 x \sinh \left( x ^ { 2 } + 1 \right)$
C) $\sinh ( 2 x )$
D) $- \sinh ( 2 x )$
E) $x ^ { 2 } \sinh \left( x ^ { 2 } + 1 \right)$