When propyne is treated with aqueous $H_2SO_4$ in presence of $HgCO_4$,the major product is

Question

$\begin{array}{1 1}(a)\;\text{Propanal}\\(b)\;\text{n-propyl hydrogen sulphate}\\(c)\;\text{Acetone}\\(d)\;\text{Propanol}\end{array}$