The amount of output produced per unit of input used is referred to as ______.productivitymarginal costspecializationdivision of labor.

The correct answer is productivity.

Explanation:

Productivity is defined as the measure of output produced per unit of input used in the production process. It can be quantified in various forms, such as labor productivity, which measures output per labor hour, or total productivity, which assesses overall output relative to all inputs used. The concept of productivity is crucial for efficiency in economic activities and can significantly impact a business's profitability and competitiveness. By enhancing productivity, businesses can produce more goods or services without a corresponding increase in input, leading to better resource utilization. In contrast, marginal cost refers to the cost of producing one additional unit, while specialization and division of labor focus on the breakdown of tasks among workers to improve efficiency, but do not directly measure output relative to input.