1. Karen Hefner, a florist, operates retail stores in sereral shopping malls. The average selling price is $35 per unit, and the average variable cost is $20 per unit. A new mall is opening where Karen wants to locate a store, but the location manager is not sure about the rent method to accept. The mall operator offers the following three options for its retail store rentals independently: 1. paying a base rent of $18,000a month, or 2. paying a base rent of $11,960 plus 10% of revenue received (sale price constant), or 3. paying a base rent of $7,520 plus 20% of revenue received (sale price constant). b. Compute the monthly rent paid at s