Convert to the polar form $r e^{i \theta} .$ For Problems 15 and 16, choose $\theta$ in degrees, $-180^{\circ} < \theta \leq 180^{\circ} ;$ for Problems 17 and 18 choose $\theta$ in radians, $-\pi < \theta \leq \pi$ Compute the modulus and arguments for parts $A$ and $B$ exactly; compute the modulus and argument for part C to two decimal places.
(A) $\sqrt{3}-i$
(B) $-2+2 i$
(C) $6-5 i$