Answer:
Option D
Explanation:
$\frac{\sqrt{7}+\sqrt{5}}{\sqrt{7}-\sqrt{5}}=(\frac{\sqrt{7}+\sqrt{5}}{\sqrt{7}-\sqrt{5}})\times\frac{\sqrt{7}-\sqrt{5}}{\sqrt{7}+\sqrt{5}}$
$=\frac{(\sqrt{7}+\sqrt{5})^{2}}{\sqrt{7}^{2}-\sqrt{5}^{2}}=\frac{(\sqrt{7}+\sqrt{5})^{2}}{7-5}$
$=\frac{7+5+2\sqrt{35}}{2}=\frac{12+2\sqrt{35}}{2}=6+\sqrt{35}$
