What must pilots obtain when flying in the vicinity of Class B airspace?

When flying in the vicinity of Class B airspace, pilots are required to obtain clearance from Air Traffic Control (ATC). Class B airspace is typically found around major airports and is designed to manage high-density air traffic. The clearance ensures that aircraft are sequenced and safely integrated into the busy flight paths leading to and from these airports.

Obtaining this clearance involves communicating with the ATC facility responsible for that airspace, which allows pilots to receive important information regarding traffic and any necessary instructions for safe navigation. This requirement is critical for maintaining safe operations, as Class B airspace often has a significant concentration of commercial and general aviation flights.

Having this understanding of the traffic environment is essential for both pilot safety and efficiency in airspace management. Other options mentioned do not specifically fulfill the requirement for entering Class B airspace; thus, it is clear why clearance from ATC is the correct choice.