Question #44963

An optically active \ce{D}-ketohexose $\textbf{X}$ gives a positive Tollens' test. In the alkaline medium of the reagent, $\textbf{X}$ undergoes the Lobry de Bruyn–van Ekenstein transformation via an intermediate $\textbf{I}$ to form an equilibrium mixture containing $\textbf{X}$ and two aldohexoses $\textbf{Y}$ and $\textbf{Z}$. Oxidation of $\textbf{Y}$ and $\textbf{Z}$ with warm \ce{HNO3} yields aldaric acids $\textbf{P}$ and $\textbf{Q}$, respectively. It is observed that $\textbf{P}$ is optically inactive (meso) while $\textbf{Q}$ is optically active. Which of the following correctly identifies $\textbf{X}$, the intermediate $\textbf{I}$, and the stereochemical relationship between $\textbf{Y}$ and $\textbf{Z}$?