Refer to figure.
The Primary Flight Display (PFD) displays information dedicated to piloting the helicopter. It incorporates various flight instruments and displays essential data such as attitude, airspeed, barometric height, radio height, vertical speed, and horizontal situation including heading information. The PFD also shows ILS localiser and glideslope deviation, autopilot modes, flight director modes, and TCAS traffic and resolution advisories.

“On the PFD, the collective is shown horizontally at the bottom in a desaturated format.” → CORRECT. The autopilot collective control is typically represented on the PFD. It appears as a horizontal scale or "power bug" at the bottom of the display. When the autopilot is managing the collective but is not in an "active" or "upper" mode that provides full-color command guidance, it may appear in a desaturated (gray or white) format to indicate its status or availability without being the primary active vertical guidance mode at that moment.

“On the FMC, the collective is displayed horizontally only.” → INCORRECT. The Flight Management Computer (FMC) or its display unit (MCDU) is primarily used for flight planning, navigation data entry, and performance calculations. It does not serve as the primary real-time display for dynamic flight control indications like the collective scale.

“On the FMC, the collective is displayed vertically.” → INCORRECT. As mentioned above, the FMC is not the interface for flight instrument scales. Primary flight parameters are always centralized on the PFD.

“On the PFD, the collective is displayed vertically with full color, and no FMC or notification is provided.” → INCORRECT. While the collective is shown on the PFD, it is generally a horizontal indicator at the bottom rather than a vertical one (vertical scales are reserved for Airspeed and Altitude). Furthermore, "full color" usually denotes an active commanded mode, whereas desaturated formats are used for specific standby or background autopilot statuses.