Which of the following functions will result in the composition $f(g(x))$ not being a function of real values?

A. $f(x)=-x^2$, $g(x)=\sqrt{x}$

B. $f(x)=\ln(x)$, $g(x)=-x^2$

C. $f(x)=x^2$, $g(x)=-x^2$

D. $f(x)=-x^2$, $g(x)=x^2$

E. $f(x)=\sqrt{x}$, $g(x)=-x^2$

F. $f(x)=-x^2$, $g(x)=\ln(x)$

G. None of the above.

Hint: