Factor by Grouping $$a x ^ { 4 } - x ^ { 4 } + 2 a - 2$$

Multiple Choice

Factor by grouping. $$a x ^ { 4 } - x ^ { 4 } + 2 a - 2$$

A) $a x ^ { 4 } + 2 a - \left( x ^ { 4 } + 2 \right)$
B) $\left( x ^ { 4 } + 2 \right) a - x ^ { 4 } - 2$
C) $\left( x ^ { 4 } + 2 \right) ( a - 1 )$
D) $x ^ { 4 } + 2 ( a - 1 )$
E) $\left( x ^ { 4 } - 2 \right) a + x ^ { 4 } + 2$