Which statement is correct for both butanal and butanone?
They both react with Tollens' reagent to form a silver mirror.
They both react with HCN\text{HCN}HCN in the presence of KCN\text{KCN}KCN to form an optically active product.
They both can be reduced by NaBH4\text{NaBH}_4NaBH4 to form secondary alcohols.
They both undergo nucleophilic addition when reacted with NaBH4\text{NaBH}_4NaBH4, initiated by the attack of a hydride ion (:H−:\text{H}^-:H−).