At what point on the total product curve shown above will marginal product be negative?

Explanation

Marginal product is negative at point S on the total product curve. This is because the total product curve is decreasing at point S. When the total product curve is decreasing, the marginal product is negative.

The marginal product is the additional output that is produced when one additional unit of input is added. In this case, the additional output is decreasing, so the marginal product is negative.

The other points on the total product curve, P, Q, and R, are all increasing. Therefore, the marginal product is positive at these points.