The correct answer is A. cost estimation.
Cost estimation is the process of predicting the cost of a product or service. It is used in a variety of industries, including manufacturing, construction, and software development. Cost estimation can be based on historical data, expert judgment, or a combination of both.
Price estimation is the process of predicting the price that a product or service will sell for. It is used in a variety of industries, including retail, wholesale, and manufacturing. Price estimation can be based on historical data, market research, or a combination of both.
Unit estimation is the process of predicting the number of units that will be produced or sold. It is used in a variety of industries, including manufacturing, construction, and retail. Unit estimation can be based on historical data, market research, or a combination of both.
Production estimation is the process of predicting the amount of output that will be produced. It is used in a variety of industries, including manufacturing, construction, and agriculture. Production estimation can be based on historical data, market research, or a combination of both.
In the given question, the relationship based on unrelated level of activity and past data of cost is measured with help of cost estimation. This is because cost estimation is the process of predicting the cost of a product or service, which can be based on historical data or expert judgment.