$...$ Suppose the yield on a two year Treasury security is $5\mathrm{.}83\%,$ and the yield on a five$-$year Treasury security is $6\mathrm{.}20\%.$ Assuming that the pure expectations theory is correct, what is the market's estimate of the three$-$year Treasury rate two years from now? a$.6\mathrm{.}61\%$ b$.5\mathrm{.}41\%$ c$.6\mathrm{.}45\%$ d$.7\mathrm{.}10\%$