To make a revision of altitude or speed associated with a waypoint, which key would you use?

To revise altitude or speed associated with a waypoint, the appropriate action involves utilizing a right line select key on the Multi-Function Control Display Unit (MCD). This is because the MCD is specifically designed to interface with waypoints and related flight data. When a waypoint is selected on the MCD, the right line select key provides access to modify information such as altitude and speed parameters assigned to that waypoint, allowing for precise adjustments as needed during flight planning or execution.

In this context, the other choices offer functionalities that do not directly translate to changing waypoint-associated altitude or speed. For example, the PERFORMANCE button on the MCK generally caters to broader system performance adjustments rather than waypoint-specific settings. Similarly, the left line select key on the MCD and the Position Fix button on the MCK serve different operational purposes, focusing on waypoint selection and positional data input respectively. Thus, using the right line select key is the correct method to effectively revise altitude or speed at a waypoint.