A$.$ ENGINEWORKS makes a line of engines for watercraft. Below is their forecast for the first $6$ months next year. They want to cost out a level production plan of $1250$ units per month using their full time employees. $*$Beginning Inventory is $100$ units. Inventory holding costs are $$45$ per unit per month. Backorder costs are $$70$ per unit per month. Regular labour is $$225$ per unit.