Answer:
The correct answer is the last option: Real output per unit of input.
Step-by-step explanation:
To begin with, in the microeconomics and business management field the concept known as "productivity" refers to the measurement related to the efficiency of production of goods or services and it is most commonly expressed as a ratio of an aggregate output to a single input so therefore that this index is very important to the companies and the governments in order to understand how the production can improve and more important how can evolve regarding the machinery and the inputs that either the business or the government.