If \(x = \frac{{\sqrt 7\; - \;\sqrt 5 }}{{\sqrt 5\; + \;\sqrt 7 }}\) and y is reciprocal of x, then what is the value of \(\sqrt {\left( {{x^3} + {y^3}} \right)}\)?

• A. 5√47
• B. 6√47
• C. 3√47
• D. √47