A $5-$year $$80,000$ consumer loan is to be paid off with monthly payments of $$1,779\mathrm{.}56.$ What monthly interest rate is to be paid? a$)1\mathrm{.}0\%$ b$)1\mathrm{.}5\%$ c$)2\mathrm{.}0\%$ d$)2\mathrm{.}2\%$