Differentiate $f ( x ) = \left( x ^ { 2 } + 1 \right) ( x + 3 )$

Multiple Choice

Differentiate: $f ( x ) = \left( x ^ { 2 } + 1 \right) ( x + 3 )$

A) 2x + 1
B) 6x + 1
C) $3 x ^ { 2 } + 6 x + 1$
D) $x ^ { 2 } + 1$