The Mean Value Theorem does not apply to
A. $f(x)=\frac{x}{x^{2}-4}$ on $[0,1]$,
B. $f(x)=\frac{x}{x^{2}+4}$ on $[0,1]$,
C. $f(x)=\frac{\sqrt{4-x}}{x}$ on $[1,4]$,
D. $\quad f(x)=\frac{e^{x}}{4 e^{x}-1}$ on $[-1,1]$,
E. $f(x)=\frac{\sqrt{\sin ^{2} x}}{e^{x}}$ on $[-3,2]$,