The parametric equations of the curve $x^{2/3}+y^{2/3}=a^{2/3}$ are

Question

$$\begin{array}{1 1}(1)x=a \sin^{3}\theta:y=a\cos^{3}\theta&(2)x=a\cos^{3}\theta:y=a\sin^{3}\theta\\(3)x=a^{3}\sin\theta:y=a^{3}\cos\theta&(4)x=a^{3}\cos\theta:y=a^{3}\sin\theta\end{array}$$