What month system does the Gregorian calendar incorporate?

The Gregorian calendar is structured around a system that organizes the year into 12 distinct months. This structure was introduced by Pope Gregory XIII in 1582 to correct discrepancies in the Julian calendar and align the calendar year with the astronomical year. Each of the 12 months has a set number of days, varying from 28 to 31, depending on the month.

This 12-month system is widely used internationally today and provides a coherent framework for both civil and religious purposes. The emphasis on a 12-month year allows for a consistent cycle of seasons and festivals, making it easier to plan agricultural activities, religious celebrations, and societal events throughout the year. The other options are not applicable because they do not correspond to the calendar structure recognized in the Gregorian system.