What will the product of the given reaction?

The correct answer is option 1.

Sodium borohydride \((NaBH_4)\) is a convenient source of hydride ion \((H^-)\) for the reduction of aldehydes and ketones. Ketones are reduced to secondary alcohols. As a source of hydride ion, \(NaBH_4\) will also act as a strong base, deprotonating water, alcohols, and carboxylic acids.

The reduction of ketones results in the formation of secondary alcohols. A \(C-H\) bond is formed and a \(C–O\) (pi) bond is broken.

The mechanism for these reductions follows the very common two-step addition-protonation pattern often found in reactions of aldehydes and ketones.

The first step in this reaction is nucleophilic addition to the carbonyl carbon forming a \(C-H\) bond and breaking a \(C–O\) (pi) bond.