Final answer:
Restricted areas are depicted on sectional charts, which are crucial for pilots to understand airspace restrictions for both military and civilian aviation.
Step-by-step explanation:
Restricted areas, which are designated by an 'R' followed by a number (such as R-4401), are depicted on a) Sectional charts. These special use airspace areas are established for security, safety, or other reasons associated with the national defense. They are represented on sectional aeronautical charts which are used by pilots to navigate during flight. These charts provide a wealth of information including the layout of restricted areas, which are essential for pilots to know in order to avoid unauthorized airspace. While restrictions are often depicted on Air Traffic Control radar screens and can be found in the Aeronautical Information Publication (AIP), they are not exclusively on military aircraft charts as restricted areas can pertain to both military and civilian pilots.