Concept:A proportional tax charges the same percentage of income as tax to every taxpayer.Explanation:Mr. Patrick pays N90 tax on an income of N900.His tax rate is 90090×100=10%.Mr. Shodawe pays N130 tax on an income of N1300.His tax rate is 1300130×100=10%.Both taxpayers pay the same 10% rate regardless of income level.Therefore, the tax system is proportional.Answer:D. Proportional