Wolff-kishner reduction (hydrazine, koh, ethylene glycol, 130°c) of the compound shown gave compound a. treatment of compound a with m−chloroperoxybenzoic acid (mcpba) gave compound b, which on reduction with lithium aluminum hydride gave compound c. oxidation of compound c with chromic acid gave compound d (c9h14o). identify compounds a through d in this sequence, and do not indicate stereochemistry.

The scheme is shown below, the steps involved are as follow,

Step one: Reduction:
               The carbonyl group of given compound on reduction using Wolf Kishner reagent converts the carbonyl group into -CH₂- group.

Step two: Epoxidation:
              The double bond present in starting compound when treated with m-CPBA (meta-Chloroperoxybenzoic acid) gives corrsponding epoxide.

Step three: Reduction:
                The epoxide is reduced to alcohol on treatment with Lithium Aluminium Hydride (LiAlH₄) followed by hydrolysis.

Step four: Oxidation:
               The hydroxyl group (alcohol) is oxidized to carbonyl (ketonic group) using oxidizing agent Chromic acid (H₂CrO₄).