Final answer:
VSO represents the minimum steady-flight speed or stalling speed in the landing configuration for aircraft which is critical to prevent stalling during landing.
Step-by-step explanation:
The correct symbol for the minimum steady-flight speed or stalling speed in the landing configuration is often represented as VSO. This is the stalling speed or the minimum steady flight speed in the landing configuration with landing flaps and landing gear deployed.
An aircraft must maintain a speed above the stalling speed to ensure adequate lift is generated by the wings to support the weight of the aircraft and prevent stalling, especially critical during landing approaches.