Find the First Harmonic of the Function $h(x)=$ $\left\{\begin{array}{l}\pi \\0\end{array}\right.$ $\begin{aligned}-\pi &<\\0<\end{aligned}$

Multiple Choice

Find the first harmonic of the function $h(x) =$$\left\{\begin{array}{l}\pi \\0\end{array}\right.$$\begin{aligned}-\pi &<\\0<\end{aligned}$$\begin{array}{l}x \leq 0 \\x \leq \pi\end{array}$ .

A) $-\sin x$
B) $\sin x$
C) $-2 \sin x$
D) $2 \sin x$
E) 0