If Possible, Factor the Polynomial Completely $$x ^ { 4 } - 1$$

Multiple Choice

If possible, factor the polynomial completely. If a polynomial cannot be factored, state that it is prime.
- $$x ^ { 4 } - 1$$

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