The terminal alkyne shown is treated with a hindered borane (such as disiamylborane) and then with $\mathrm{H}{}_2\mathrm{O}{}_2$/$\mathrm{NaOH}$. Which structure is the product?

The compound shown is pent-1-yne. Hydroboration puts boron on the terminal carbon (anti-Markovnikov); oxidation gives an enol that tautomerises to pentanal. The ketone is the product of mercury-catalysed hydration. The alcohol and the acid would need further reduction or oxidation, which the reagents do not do.