A project milestone is set to be completed in $50$ days. The project manager estimates the completion time follows a normal distribution with a mean of $55$ days and standard deviation of $5$ days. What is the probability that the milestone will be completed in $50$ days or less?

$0\mathrm{.}8413$

$0\mathrm{.}6915$

$0\mathrm{.}1587$

$0\mathrm{.}3085$