Which of the following compounds does not undergo aldol condensation?

The major product of the following reaction is:

Compound $(A)$ with molecular formula $C_6H_{12}O_3$ gives a positive iodoform test and a negative Tollens' test. Upon treatment with water and a drop of $H_2SO_4$,it gives a positive Tollens' test. Compound $(A)$ is:

Predict the product of the following reaction:
$3$-hydroxycyclopentanone $\xrightarrow{Zn-Hg/HCl}$ product

$A$ carbonyl compound $X$ $(C_8H_8O)$ undergoes disproportionation with conc. $KOH$ on heating. The product of $X$ with $Zn-Hg/HCl$ is $Y$ and the product of $X$ with $NaBH_4$ is $Z$. What are $Y$ and $Z$ respectively?

Which one among the following compounds will most readily be dehydrated under acidic condition?