1.CH₃CH₂CH(OH)COOH
2.CH₃CH₂CH(OH)CN
3.CH₃CH₂CH(OH)CH₂NH₂
4.CH₃CH₂CH₂CH₂NH₂
Correct answer:(3)
Cyanohydrin becomes amino alcohol
When carbonyl compounds react with HCN to form corresponding cyanohydrins. When these cyanohydrines are reducing with strong reducing agents like Lithium aluminium hydride to form amino alcohols.

ALDEHYDES react with HCN
It is a Nucleophilic addition reaction When propionaldehyde react with HCN to form propionaldehyde cyanohydrin, Which wind followed by reducing with Lithium aluminium hydrate to form 4-amino-2- butanol.
Consider the following sequence of reactions CH₃CH₂CHO → (KCN / H₂SO₄) → A → (1. LiAlH₄ 2. H₂O) → B