Square roots of -i, where $${\text{i}} = \sqrt { - 1} ,$$   are

A. $${\text{i}},\, - {\text{i}}$$

B. $${\text{cos}}\left( { - \frac{\pi }{4}} \right) + {\text{i}}\sin \left( { - \frac{\pi }{4}} \right),\,\cos \left( {\frac{{3\pi }}{4}} \right) + {\text{i}}\sin \left( {\frac{{3\pi }}{4}} \right)$$

C. $${\text{cos}}\left( {\frac{\pi }{4}} \right) + {\text{i}}\sin \left( {\frac{{3\pi }}{4}} \right),\,\cos \left( {\frac{{3\pi }}{4}} \right) + {\text{i}}\sin \left( {\frac{\pi }{4}} \right)$$

D. $${\text{cos}}\left( {\frac{{3\pi }}{4}} \right) + {\text{i}}\sin \left( { - \frac{{3\pi }}{4}} \right),\,\cos \left( { - \frac{{3\pi }}{4}} \right) + {\text{i}}\sin \left( {\frac{{3\pi }}{4}} \right)$$

Answer: Option B