What type of information is displayed as airspeed on the PFD?

The correct choice reflects that the information displayed as airspeed on the Primary Flight Display (PFD) includes reference speeds, Mach number display, and low/high speed cues.

In aviation, understanding airspeed is crucial for safe flight operations. Reference speeds — such as stall speed, V1, V2, and Vref — are essential for pilots to make informed decisions during takeoff, landing, and in-flight maneuvers. The Mach number display is vital for pilots flying at high altitudes or speeds, allowing them to monitor and manage the aircraft’s performance relative to the speed of sound. Additionally, low and high-speed cues provide visual indications to the pilot, helping them to maintain safe operational parameters and manage the aircraft effectively.

The other options do not pertain to airspeed information directly displayed on the PFD. Current altitude and vertical speed are related to altitude management rather than airspeed. Ground speed and heading relate to the aircraft's movement over the ground, while throttle position and engine RPM focus on engine performance rather than the speed of the aircraft through the air.