Solve the Problem $v=45,600+100 t^{2}$ , Where $t$ Is the Number of Years from Now

Solve the problem.
-It is estimated that the total value of a stamp collection is given by the formula $v=45,600+100 t^{2}$ , where $t$ is the number of years from now. If the inflation rate is running continuously at $4 \%$ per year so that the (discounted) present value of an item that will be worth $\$ v$ in $t$ years' time is given by $\mathrm{p}=\mathrm{ve}^{-.04 \mathrm{t}}$ . Sketch the graph of the discounted value as a function of time at which the stamp collection is sold. What are the values of $t$ at the points of inflection?

A) $t=19.52$ and $t=81.28$ .
B) $\mathrm{t}=24.92$ and $\mathrm{t}=77.38$ .
C) $t=19.82$ and $t=86.18$ .
D) $\mathrm{t}=21.82$ and $\mathrm{t}=78.18$ .