Calculate the accumulated value after twenty years of payments of $$12000\mathrm{.}00$ made at the end of each year if interest is $6\%$ compounded semi$-$annually. a$$445721\mathrm{.}73$ b$$322444\mathrm{.}73$ c$$642766\mathrm{.}07$ d$$240000\mathrm{.}00$ e$$441427\mathrm{.}09$