For the curve $x=e^{t}\cos t: y=e^{t}\sin t$ the tangent line is parallel to the $x$-axis when $t$ is equal to

Question

$$\begin{array}{1 1}(1)-\frac{\pi}{4}&(2)\frac{\pi}{4}\\(3)0&(4)\frac{\pi}{2}\end{array}$$