The volatility of a stock is $20\%$ and the risk$-$free rate is $5\%,$ both per annum and with continuous compounding. Which of the following is closest to the Cox, Ross, and Rubinstein estimate of risk$-$neutral probability p for a binomial tree with a one$-$week time step?

$0\mathrm{.}339$

$0\mathrm{.}624$

$0\mathrm{.}417$

$0\mathrm{.}511$