A company is considering three different compensation plans for its sales representatives, whose effort levels are difficult to monitor directly. Your task is to analyze the plans from the perspective of a rational representative who seeks to maximize their personal net income (earnings minus personal costs).

Based on the case details provided, determine for each plan whether the representative would choose a high or low level of effort. Which plan, if any, successfully motivates the representative to exert high effort? Justify your answer with clear calculations.