Which of the following is considered a service?

A haircut is considered a service because it involves a professional providing an action or performance to meet a need or demand. Services are intangible and cannot be physically possessed; instead, they are experienced or utilized. When you get a haircut, you are benefiting from the skill and labor of the hairstylist rather than obtaining a physical product that you can own.

In contrast, the other options represent tangible goods that can be owned, such as a car, book, or smartphone. These items are physical products that you can purchase, possess, and use, which differentiates them from services. Understanding the distinction between goods and services is fundamental in exploring business concepts, as it affects how products are marketed, sold, and consumed.