Who has given the concept of consumer surplus?

The correct answer is A. Marshall.

Alfred Marshall was an English economist who is considered one of the most influential economists of the 19th century. He is best known for his work on microeconomics, including his development of the concept of consumer surplus.

Consumer surplus is the difference between the maximum amount that a consumer is willing and able to pay for a good and the price that they actually pay. It is a measure of the benefit that consumers receive from consuming a good.

Marshall developed the concept of consumer surplus in his book “Principles of Economics,” which was published in 1890. He argued that consumer surplus is an important concept because it helps to explain how markets work.

In a competitive market, the price of a good will be equal to the marginal cost of production. The marginal cost of production is the cost of producing one additional unit of a good.

If the price of a good is equal to the marginal cost