Evaluate the integral ${\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}\frac{26x^2}{\sqrt[\phantom{2}]{9-x^2}}dx.$

a$.$ Which trigonometric substitution is correct for this integral?

A$.x=3tan()$

B$.x=3sec()$

C$.x=9sin()$

D$.x=9tan()$

E$.x=9sec()$

F$.x=3sin()$

b$.$ What integral do you obtain after substituting for $x$ and simplifying?

c$.$ What is the value of the above integral in terms of $?$

d$.$ What is the value of the original integral in terms of $x?$