Which one of the following compounds is the best choice for being prepared by an efficient mixed aldol addition reaction?

What is the product formed when acetaldehyde reacts with $PCl_5$?

An organic compound $A$ is oxidized using acidified $K_2Cr_2O_7$ solution to form compound $B$. Compound $B$ gives the $DNP$ test but not the silver mirror test. Then,compound $A$ is:

Product $(D)$ will be

$CH_3CHO$ reacts with aqueous $NaOH$ solution to form

Given below are two statements:
Statement $I$: $H_2N-CO-CH_2-CH_2-CO-CH_3$ under Clemmensen reduction conditions will give $HOOC-(CH_2)_3-CH_3$.
Statement $II$: $CH_3-CH(CH_3)-CH_2-CH(Cl)-CO-CH_3$ under Wolff-Kishner reduction conditions will give $CH_3-CH(CH_3)-CH_2-CH(Cl)-CH_2-CH_3$.
In the light of the above statements,choose the correct answer from the options given below: