The correct option is D CH3CH2COCl→CH3CH2CHO:H2,Pd/BaSO4
(a) Tollen's reagent refers to the chemical reagent which is used in the detection of an aldehyde functional group in a given test substance.
Ketones don't give silver mirror with Tollens' reagent.
Tollen's reagent is a solution of silver nitrate (AgNO3) and Ammonia (NH3).
A postive test gives precipitate of elements silver.RCHO+2[Ag(NH3)2]++3OH−→RCOO− + 2Ag↓ + 2H2O+4NH3Aldehyde Tollen's Reagent Carboxylate ion Silver mirror
(b) KMnO4 oxidises aldehyde to carboxylic acid as it is an oxidising agent.
(c) NaBH4 reduces aldehyde to primary alcohol.
(d) H2,Pd/BaSO4 reduces carbonyl chloride to aldehyde.
Hence, (a), (c) and (d) are correct.