According to your regression analysis performed for part $42,$ what is the approximate average rate of change of monthly income? $($Round to two $[2]$ decimal places.$)q,$ a$.2\mathrm{.}15\%$ per month.

b$.$ $$80\mathrm{.}01$ per month.

c$.$ $$48\mathrm{.}55$ per month.

d$.89\mathrm{.}45\%$ per month.

e$.$ $$2146\mathrm{.}70$ per month.