#### Answer

B

#### Work Step by Step

Note that $x^4=(x^2)^2$ and $1=1^2$.
Thus, the given binomial can be written as:
$=(x^2)^2-1^2$
Factor using the formula $a^2-b^2=(a+b)(a-b)$ where $a=x^2$ and $b=1$ to obtain:
$=(x^2+1)(x^2-1)$
Factor the second binomial using the same formula with $a=x$ and $b=1$ to obtain:
$=(x^2+1)(x+1)(x-1)$
Therefore, the answer is Option B.