The Marginal Physical Product (MPP) is the additional output resulting from using an additional unit of input, keeping all other inputs constant.

It’s calculated as the change in total output divided by the change in the quantity of an input.

From the table in the image, the total output for 4 units of input is 20, and for 5 units of input, it’s 22. Therefore, the MPP of the last unit of input (from 4 to 5 units) is:

MPP = (Total Output at 5 units - Total Output at 4 units) / (5 units - 4 units)

MPP = (22 - 20) / (5 - 4)

MPP = 2 / 1

MPP = 2

So, the correct answer is 2.