Final answer:
The ILS Localizer is a key part of the Instrument Landing System that provides lateral guidance to align aircraft with the runway. An additional navigation function would likely enhance the guidance capabilities of the ILS Localizer.
Step-by-step explanation:
The ILS Localizer is a crucial component of the Instrument Landing System (ILS) that guides an aircraft horizontally during its approach phase to ensure alignment with the centerline of the runway for a safe landing. Specifically, the ILS Localizer provides the lateral guidance necessary to keep the aircraft on the correct approach path. When referring to the ILS Localizer Course with an additional navigation function, it primarily includes a system that enhances these guidance capabilities with additional information, likely to improve the precision and reliability of the approach.
According to the options provided, the best match for the description of an ILS Localizer with an additional navigation function is option B) A component of the ILS that guides the aircraft horizontally to align with the runway centerline. This explanation matches the primary purpose of an ILS Localizer and implies additional functionalities to further aid in achieving the goal of a well-aligned approach and landing.