In order to benchmark other cupcake stores, you visited another store over a year and observed that their service level is 90%. Their retail cupcake price is $3.99. You would like to estimate their unit cost. You learned that they donate all the leftovers, i.e., their salvage value is zero. Assume that they do their business in an optimal manner, i.e., the observed service level is the target service level. What is their unit cost