Four years from now $($beginning of year four$)$ you will receive the first of seven $$10,000$ annual payments. The current interest rate is $6\%,$ but by the beginning of year $4,$ the rate will rise to $8\%.$ What is the present value of this cash flow stream?$\backslash$

a$.$ $$55,692\mathrm{.}25\backslash$

b$.$ $$44,538\mathrm{.}48\backslash$

c$.$ $$46,864,48\backslash$

d$.$ $$42,554\mathrm{.}48\backslash$

e$.$ $$41,827\mathrm{.}25$