The most likely acid-catalysed aldol condensation products of each of the two aldehydes I and II are represented by the option (D). The product of aldol condensation of aldehyde I undergoes dehydration as the $C = C$ double bond is in conjugation with $C = O$ double bond. This leads to stability.
The product of aldol condensation of aldehyde II will not undergo dehydration as the $C=C$ double bond is not in conjugation with $C = O$ double bond due to presence of a quaternary C atom.
