1991 AHSME Problem 24

The graph, G of y=\log_{10}x is rotated 90^{\circ} counter-clockwise about the origin to obtain a new graph G'. Which of the following is an equation for G'?

\textbf{(A) } y=\log_{10}\left(\frac{x+90}{9}\right) \qquad \textbf{(B) } y=\log_{x}10 \qquad \textbf{(C) } y=\frac{1}{x+1} \qquad \textbf{(D) } y=10^{-x} \qquad \textbf{(E) } y=10^x

Full credit goes to MAA for authoring these problems. These problems were taken on the AOPS website.