Which of the following statements is true if afirm finds that with three workers it can produce 45 units?

• a.)
• The total product of labor is 15 units.
• b.)
• The marginal revenue product of the third worker is 15 units.
• c.)
• The average product of labor is 15 units.
• d.)
• The marginal product of the third worker is 15 units.