Aria operates a popular bakery in Melbourne, known for its artisanal breads. To maintain her bakery's reputation for quality, she sources a special type of flour from a nearby supplier. The details of her flour supply requirements and costs are as follows: * The supplier charges $1.20 per kilogram of flour, along with a fixed delivery fee of $30 per order, regardless of the order's size. * Aria's bakery incurs a holding cost of $0.05 per kilogram of flour per month. * To meet her bakery's production demands, Aria needs 12,000 kilograms of flour each month