If \(\sin {\rm{A}} = \frac{3}{5},\) where 450° < A < 540°, then \(\cos \frac{{\rm{A}}}{2}\) is equal to

• A. \(\frac{1}{{\sqrt {10} }}\)
• B. \(- \sqrt {\frac{3}{{10}}}\)
• C. \(\frac{{\sqrt 3 }}{{\sqrt {10} }}\)
• D. None of the above