Explain what the economic problem is​

What is the difference between total utility and marginal utility? a. marginal utility is subject to the law of diminishing marginal utility while total utility is not. b. total utility represents the consumer optimum while marginal utility gives the total utility per dollar spent on the last unit. c. total utility is the total amount of satisfaction derived from consuming a certain amount of a good while marginal utility is the additional satisfaction gained from consuming an additional unit of the good. d. marginal utility represents the consumer optimum while total utility gives the total utility per dollar spent on the last unit.