NEET 2023, Chemistry Q4: Properties and Important Reactions of Aldehydes & Ketones

Zn-Hg with concentrated HCl is the Clemmensen reduction, which converts a carbonyl group ($\text{C}=\text{O}$) directly to a methylene group (${\text{CH}}_2$).

Both ketone groups on the benzene ring are reduced to $-{\text{CH}}_2-$ linkers connecting the ring to the cyclohexyl substituents. The two oxygens leave as $2{\text{H}}_2\text{O}$.