The correct option is
D (a) and (b) above.
The given reaction is the reduction of ketones to alkanes, condensation of the carbonyl compound with hydrazine
(H2N−NH2) forms the hydrazone, and the treatment with base induces the reduction of the carbon coupled with oxidation of the hydrazine to gaseous nitrogen, to yield the corresponding alkanes is Wolff-Kishner reduction.
The Clemmensen Reduction also allows the deoxygenation of aldehydes or ketones, to produce the corresponding hydrocarbon using amalgamated zinc and hydrochloric acid but the substrate must be stable in the presence of strong acid. Therefore both (a) and (b) are correct.