What is the configuration for a single-engine approach?

In a single-engine approach, the configuration typically emphasizes safety and appropriate airspeed management for a controlled landing, which involves certain practices regarding gear, flaps, and speed.

Selecting the configuration that includes the gear down and flaps set at 10 degrees, along with the proper lighting and a reference speed (Vref) at a slightly higher setting, is essential. The gear being down ensures that the aircraft is in a landing configuration, providing better aerodynamic stability and the ability to manage descent rate effectively. The flaps deployed to 10 degrees increase lift and slow the aircraft down, enabling a safer landing approach.

Furthermore, using Vref +10 allows for an additional buffer in speed, considering that in a single-engine scenario, the aircraft's performance needs to account for reduced power and potential additional drag from the configuration changes. The inclusion of lights ensures that the aircraft is visible and complies with visibility requirements during the landing phase, contributing to overall safety.

The other configurations may either not prioritize safety correctly or do not align with the standard practices for single-engine approaches, making option C the most suitable choice for ensuring effective management of the approach and landing under these conditions.