Which of the following compounds can show an aldol condensation reaction?

Which among the following reagents cannot be used for the above interconversion? The reaction involves the reduction of a ketone group $(>C=O)$ to a methylene group $(-CH_2-)$.

Which of the following is not a final product obtained by cross aldol condensation of ethanal and propanal?

In the given reaction sequence,identify the structure of $(B)$:
Cyclohexanol $\xrightarrow{PCC}$ $(A)$ $\xrightarrow{H-CHO, \text{dil. } KOH, \Delta}$ $(B)$

Identify the reaction in which the carbonyl group of aldehydes and ketones is reduced to a methylene group upon treatment with zinc-amalgam and concentrated hydrochloric acid.

What is the major product obtained in the following reaction?
[Image of a substituted cyclohexane ring with a carboxylic acid group,a vinyl group,a nitro group,and an acetyl group,reacting with excess $LiAlH_4$]