The best statement that summarizes the difference between formal and functional regions is:
2. A formal region is an area on Earth's surface defined by relatively unchanging cultural or physical traits, often associated with formal boundaries. A functional region is an area characterized by one or more activities occurring within that area, whose boundaries are usually more loosely defined.
This statement clearly distinguishes between the two types of regions by explaining that formal regions are based on established traits or characteristics, while functional regions are defined by specific activities and have flexible boundaries.