The correct option is A Solution of H2SO4
Sulphuric acid is the stronger acid of the two as for each molecule of sulphuric acid it gives out two H+ ions in comparision to HCN (hydrocyanic acid) which gives only one. Also, pH of Sulphuric Acid is much lower than hydrocyanic acid, which justifies the fact that sulphuric acid is a highly strong acid as compared to hydrocyanic acid. Hence it will produce a higher concentration of H+ ions.