On an LNAV approach, what is the Minimum Decision Altitude (MDA)?

The Minimum Decision Altitude (MDA) on an LNAV (Lateral Navigation) approach is significant in ensuring safe landing procedures under instrument flight rules (IFR). The MDA represents the lowest altitude to which a pilot can descend on an approach without having visual reference to the runway environment.

In the context of the given choices, the range of 300-500 feet as the MDA aligns with the standard operational protocols for LNAV approaches. This altitude range is designed to provide pilots with adequate vertical separation from potential obstacles and the ground while also allowing for sufficient time to conduct a visual descent to the runway upon the approach.

It's also important to recognize that the specific MDA for any given approach can vary depending on factors like terrain elevation, approach path, and decision-making authority but typically, for LNAV approaches, it falls within this bracket. The chosen range accurately reflects industry standards and operational safety considerations, making it the correct answer.