Final answer:
The correct option is 2. On a VFR sectional chart, a dash blue color indicates controlled airspace. Controlled airspace is where air traffic control services are provided and pilots need clearance to enter and operate within it.
Step-by-step explanation:
On a VFR sectional chart, a dash blue color indicates controlled airspace. Controlled airspace refers to the airspace where air traffic control services are provided.
These areas are typically surrounding busy airports or along designated flight routes. Pilots must obtain clearance from air traffic control to enter and operate within controlled airspace. Examples of controlled airspace include Class B, Class C, and Class D airspace.