\(\mathrm{CF}_{3} \mathrm{COOH}>\mathrm{CCl}_{3} \mathrm{COOH}>\mathrm{HCOOH}>\mathrm{CH}_{3} \mathrm{COOH}\)
\((B) \quad \quad \quad >\quad \quad(A) \quad \quad > \quad(D) \quad > \quad(C)\)
$PhCHO + Ph \cdot CHO \xrightarrow[in\,\,{{D}_{2}}O]{NaOD} A + \begin{matrix} O \\ || \\ Ph-C-{{O}^{-}} \\ \end{matrix}$$\left( Ph\right.$ is $\left.- C _{6} H _{5}\right)$

