Gulfstream, Inc. uses a Q$-$model to make inventory decisions about a replacement part for a door panel. Annual demand has been forecast to be $2500$ units, while it costs $$8$ to hold unit for a year and $$400$ to place an order. The order lead time is $9$ days and a service level of $98\%$ is desired. If the company operates $360$ days per year and the standgrd deviation of daily demand is $20,$ approximately how much safety stock is required? $($Round your answer to the nearest whole number.$)$

$123$

$99$

$107$

$6$