9. Calculate: $\frac{\log _{2} 80}{\log _{40} 2}-\frac{\log _{2} 160}{\log _{20} 2}=(\quad$.
(A)0
(B) 1
(C) $\frac{5}{4}$
(D) 2
(E) $\log _{2} 5$
9. D.
$$
\begin{array}{l}
\text { Original expression }=\frac{\frac{\lg 80}{\lg 2}}{\frac{\lg 2}{\lg 40}}-\frac{\frac{\lg 160}{\lg 2}}{\frac{\lg 2}{\lg 20}} \\
=\frac{\lg 80 \times \lg 40-\lg 160 \times \lg 20}{\lg ^{2} 2} \\
=\frac{(3 \lg 2+1)(2 \lg 2+1)-(4 \lg 2+1)(\lg 2+1)}{\lg ^{2} 2} \\
=\frac{2 \lg ^{2} 2}{\lg ^{2} 2}=2 .
\end{array}
$$