$\begin{matrix}
C{{H}_{3}}CHCOOH\xrightarrow{\Delta }\,Product \\
|\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, \\
OH\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, \\
\end{matrix}$
$(A)\, CH_3CO_2H$ $(B)\, MeOCH_2CO_2H$
$(C)\,CF_2CO_2H$ $(D)\,$
$PhCHO + Ph \cdot CHO \xrightarrow[in\,\,{{D}_{2}}O]{NaOD} A + \begin{matrix} O \\ || \\ Ph-C-{{O}^{-}} \\ \end{matrix}$$\left( Ph\right.$ is $\left.- C _{6} H _{5}\right)$