How many hours are in one day?

The correct answer is based on the universally accepted division of time. A day is defined as the span of time it takes for the Earth to complete one full rotation on its axis relative to the sun, which is 24 hours. This period is divided into smaller units—hours, minutes, and seconds—that measure time consistently across various contexts, including scientific and everyday applications.

Understanding that a day consists of 24 hours is fundamental in various aspects, such as scheduling, time management, and even healthcare practices, where precise timekeeping is essential. Since the other options do not align with the standard measurement of a day, they do not accurately represent how time is traditionally calculated.