The expression, "There's no such thing as a free lunch" implies that: a. the person consuming a good must always pay for it. b. everyone has to pay for his/her own lunch. c. no one has time for a good lunch anymore. d. costs must be incurred when resources are used to produce goods and services.

d. costs must be incurred when resources are used to produce goods and services.

Explanation:

Opportunity cost has to do with alternatives let go (sacrificed) to produce a particular product or service. Thus for every good and service, apart from the opportunity cost of producing or rendering a service, there is an actual cost incurred in producing them. There is no free good or service, the processes of converting raw materials to finished goods is capital intensive and not free. There is no free lunch.