Heading and course adjustments on the EHSI are made through which component?

The correct answer is the EFIS control panel. This component is specifically designed to allow pilots to input and adjust various parameters related to the Electronic Flight Instrument System (EFIS), including heading and course adjustments. The layout and functionality of the EFIS control panel provide a user-friendly interface where pilots can easily make real-time changes to navigation settings, enhancing situational awareness and flight management.

Other components listed, such as the autopilot interface, manage automated flight controls but typically do not facilitate direct manual inputs for heading and course adjustments. The flight management system serves a broader role in route planning and navigation but may not allow for immediate adjustments like the EFIS control panel does. Manual flight controls are primarily focused on aircraft maneuvering and do not interact with electronic navigation settings. Thus, the EFIS control panel is the appropriate choice for making heading and course modifications on the EHSI.