Consider a local plzza parlor that tracks productivity to improve operational efficiency. Management is exploring different ways to measure how effectively inputs like labor, equipment, and ingredients are converted into output. Which one of the following is not a valid productivity measure?

Pizzas produced per cost of ingredients

Labor hours per pizzas produced

Pizzas produced per number of ovens used

Selling price of pizzas per cost of workers and ingredients

Selling price of pizzas per number of workers used