Convert from rectangular to polar coordinates:

Note: Choose $r$ and $\theta$ such that $r$ is nonnegative and $0 \leq \theta < 2\pi$

$\mathbf{(a)}\quad (2,0)\quad\Rightarrow_{(r,\theta)}\quad$(,)

$\mathbf{(b)}\quad(12,\frac{12}{\sqrt{3}})\quad\Rightarrow_{(r,\theta)}\quad$(,)

$\mathbf{(c)}\quad(-3,3)\quad\Rightarrow_{(r,\theta)}\quad$(,)

$\mathbf{(d)}\quad(-\sqrt{3},1)\quad\Rightarrow_{(r,\theta)}\quad$(,)