What are the vertical limits of a transition area?

The vertical limits of a transition area are indeed defined as being from 700 feet above ground level (AGL) to the base of the surrounding controlled airspace. This configuration is specifically designed to provide a buffer where aircraft can transition between uncontrolled airspace and the more regulated controlled airspace.

The rationale behind starting at 700 feet AGL is aligned with the minimum altitude regulations and allows for safe operations of visual flight rules (VFR) traffic beneath the controlled airspace while providing a defined space for aircraft to enter and exit controlled airspace vertically without conflict. This transition area serves as a way to manage traffic efficiently and maintain safety during these operations.

The other options do not accurately describe the vertical limits for a transition area. Some may reference altitudes that do not correspond with FAA specifications for these airspace designations or are incomplete in their definitions. Thus, the proper understanding of how transition areas are structured is critical for both maintaining safe altitudes and executing proper VFR operations near airspace boundaries.