The terminal alkyne shown is converted with disiamylborane followed by $\mathrm{H}{}_2\mathrm{O}{}_2$/$\mathrm{NaOH}$. Which structure is the product?

The compound shown is 3-methylbut-1-yne. Hydroboration-oxidation is anti-Markovnikov and delivers the aldehyde 3-methylbutanal. Mercury-catalysed hydration would instead give the ketone 3-methylbutan-2-one. The alcohol and acid are over-reduced or over-oxidised forms that do not arise here.