Which of the following undergoes a reaction with $50\%$ sodium hydroxide solution to give the corresponding alcohol and acid?

This is the Cannizzaro's reaction, which occurs for aldehydes that do not have an $\alpha$ -hydrogen.Benzaldehyde (${\text{C}}_6{\text{H}}_5\text{CHO}$) has no $\alpha$ -hydrogen.When treated with concentrated $\text{NaOH}$, it undergoes self-oxidation and reduction (disproportionation) to form benzyl alcohol and sodium benzoate.Butanal has $\alpha$ -hydrogens and undergoes aldol condensation.