To determine when a person should consume more of something, we should understand the relationship between marginal cost and marginal benefit. The correct answer is:
d) benefit exceeds its marginal cost.
This means that as long as the additional benefit gained from consuming one more unit of a good or service is greater than the cost incurred by consuming that extra unit, it makes sense to increase consumption. If the benefit you gain from the next unit is higher than what you have to pay (or the additional cost you bear), then you are making a rational choice in consuming more. This principle helps individuals and businesses maximize their utility or profit by ensuring they only consume or produce more when it’s advantageous to do so.