Find the value of $$\left(\frac{9^{3} + 9^{4} + 9^{5} + 9^{6} + 9^{7}}{9^{1} + 9^{2} + 9^{3} + 9^{4} + 9^{5}}\right)^{\frac{1}{2}}$$

A

9

B

3

C

729

D

81