Smooth Talk offers cell phone service utilizing three distribution channels. Profit, advertising cost and personal sales time data for each of the distribution channels are given below. Due to supply chain issues, the distributor for Smooth Talk can only produce 1200 units per period. Distribution Channel Profit Per Unit sold Advertising cost per Personal sales effort unit sold per unit sold. Easy Talk stores $75 $10 4 hours Mail Orders $65 $16 None Local departmental $89 4 Hours stores What is the objective function formula for maximizing profit