Answer:
The correct answer is B. Quantity of output per unit of input.
Productivity is a measure of efficiency that relates the amount of output produced to the amount of input used. The most commonly used definition of productivity is the amount of output produced per unit of input. This definition can be expressed mathematically as:
Productivity = Output / Input
In this formula, the input can be measured in a variety of ways, such as labor hours, capital invested, or raw materials used. The output can also be measured in a variety of ways, such as units produced, services provided, or revenue generated.
Therefore, productivity is generally defined as the quantity of output per unit of input, which means that answer B is the correct choice.