The correct answer is A. total utility and marginal utility.
Total utility is the total satisfaction a consumer gets from consuming a good or service. Marginal utility is the additional satisfaction a consumer gets from consuming one more unit of a good or service.
A consumer gets maximum satisfaction where the marginal utility of a good or service is equal to the price of the good or service. This is because the consumer is getting the same amount of satisfaction from each additional unit of the good or service, and they are not willing to pay more for additional units.
If the marginal utility of a good or service is greater than the price of the good or service, the consumer will get more satisfaction from consuming more of the good or service. They will continue to consume more of the good or service until the marginal utility is equal to the price.
If the marginal utility of a good or service is less than the price of the good or service, the consumer will get less satisfaction from consuming more of the good or service. They will stop consuming the good or service until the marginal utility is equal to the price.
In conclusion, a consumer gets maximum satisfaction where the marginal utility of a good or service is equal to the price of the good or service.