Concept:When demand is perfectly inelastic, consumers do not reduce quantity demanded when price rises.Explanation:A perfectly inelastic demand means the quantity demanded stays constant regardless of price changes.If a tax is imposed on such a commodity, sellers can easily pass the entire tax burden on to buyers as a higher price.Buyers continue purchasing the same quantity even at the higher price.Therefore, the whole burden of the tax falls on the buyers.Sellers and the government bear no part of the tax burden in this case.Answer:The buyers alone.