The correct answer is: A. explicit costs
Normal profits are the minimum amount of profit that a firm must make in order to remain in business. They are equal to the opportunity costs of the firm’s resources, which are the costs that the firm would incur if it used its resources in their next-best alternative use.
Explicit costs are the costs that a firm incurs in order to produce its goods or services. They include the costs of labor, materials, and other inputs that the firm purchases from other firms.
Implicit costs are the costs that a firm incurs in order to use its own resources, such as the opportunity cost of the firm’s owner’s time and capital.
Social costs are the costs that society incurs as a result of a firm’s production, including the costs of pollution and other negative externalities.
Private costs are the costs that a firm incurs in its production, including both explicit and implicit costs.
Therefore, normal profits are equal to explicit costs.