Evaluate $\begin{align*} \int_{-1}^1 f(x) \;dx \end{align*}$, where <br> <br>$f(x) = \begin{cases} 1-2x, & x \leq 0 \\ 1+2x, & x \geq 0 \end{cases}$

Question

( A ) 6
( B ) 2
( C ) 0
( D ) 4