The correct answer is: "Factor productivity".
Factor productivity is enhanced when factors of production (land, labor and capital) are used more efficiently in a production process, so that the total output generated increases without necessarily increasing the amount of the abovementioned inputs.
For example, the productivity of capital can be represented by the number of of products that one machine is able to generate. If the quantity of inputs used remains constant, but the number of products manufactured by the machine grows, therefore the productivity of capital has increased.