Let$$s assume that a $$450,000$ monthly mortgage has a debt service of $$3,105\mathrm{.}78.$ If the amortization period is $25$ years, what is the interest rate on this mortgage?

$6\mathrm{.}24\%$

$5\mathrm{.}875\%$

$6\mathrm{.}96\%$

$6\mathrm{.}74\%$