Final answer:
Economics is defined as the study of decision-making in the context of scarcity, where unlimited human wants clash with limited resources available.
Step-by-step explanation:
Economics is the study of how humans make decisions when faced with scarcity. Scarcity signifies a condition where human unlimited wants for goods, services, and resources exceed the limited resources available. This subject involves various types of decisions, such as individual, family, business, and societal, all of which must consider the finite nature of resources, including the ultimate scarce resource: time.
The correct answer to the student's question is c. unlimited wants and limited resources.