A5. The solution to the equation $\log _{4} \log _{3} \log _{2} x=0$ is:
(A) $x=8$
(B) $x=-8$
(C) $x=0$
(D) $x=4$
(E) $x=10$
A5. First, $4^{0}=\log _{3} \log _{2} x$, then $3=\log _{2} x$ and finally $2^{3}=x$ or $x=8$.