Let $$f: R \rightarrow R$$ be a function defined $$f(x) = \frac{x}{(1+x^4)^{1/4}}$$ and $$g(x) = f(f(f(f(x))))$$ then $$18\int_0^{\sqrt{2\sqrt{5}}} x^2 g(x) \, dx$$

A

33

B

36

C

42

D

39