Convert the complex number $\;z=\large\frac{i-1}{cos \large\frac{\pi}{3} + i sin \large\frac{\pi}{3}}\;$ in the polar form

Question

$(a)\;0\qquad(b)\;\sqrt{2} (cos \large\frac{ \pi}{12} + i sin \large\frac{ \pi}{12})\qquad(c)\;\sqrt{2} (cos \large\frac{5 \pi}{12} + i sin \large\frac{5 \pi}{12})\qquad(d)\; cos \large\frac{5 \pi}{12} + i sin \large\frac{5 \pi}{12}$