Answer (2)
Sol. Since ‘A’ gives positive silver mirror test therefore, it must be an aldehyde or $\alpha$-Hydroxyketone.
Reaction with semicarbazide indicates that A can be an aldehyde or ketone.
Reaction with $\mathrm{OH}^{-}$i.e., aldol condensation (by assuming alkali to be dilute) indicates that $A$ is aldehyde as aldol reaction of ketones is reversible and carried out in special apparatus.
These indicates option (2).