What is \({\left[ {\frac{{\sin \frac{{\rm{\pi }}}{6} + {\rm{i}}\left( {1 - \cos \frac{{\rm{\pi }}}{6}} \right)}}{{\sin \frac{{\rm{\pi }}}{6} - {\rm{i}}\left( {1 - \cos \frac{{\rm{\pi }}}{6}} \right)}}} \right]^3}\) where \({\rm{i}} = \sqrt { - 1} ,\) equal to?

• A. 1
• B. i
• C. -1
• D. -i