The signal $x(t)$ is described by
$x(t)=\left\{\begin{array}{ll}
1 & \text { for }-1 \leq t \leq+1 \\
0 & \text { otherwise }
\end{array}\right.$
Two of the angular frequencies at which its Fourier transform becomes zero are
- $\pi, 2 \pi$
- $0.5 \pi, 1.5 \pi$
- $0, \pi$
- $2 \pi, 2.5 \pi$