Answer:
d. costs must be incurred when resources are used to produce goods and services.
Step-by-step 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.