Which of the following is true when a firm has reached the point of diminishing returns? a. marginal product is negative O b. marginal product is rising, but still positive O c. average product is declining O d. average product may be rising or declining O e. both a) and c) are correct

Which of the following is true when a firm has reached the point of diminishing returns? a. marginal product is negative b. marginal product is rising, but still positive c. average product is declining d. average product may be rising or declining e. both a) and c) are correct