For a professional graphics workstation, three primary elements are the host processor, the display controller, and which essential display device component?

Introduction / Context:
A graphics workstation integrates compute and visualization subsystems to render images efficiently. The question examines whether you can identify the essential display device that completes the trio with the host processor and the display controller (graphics processor or frame buffer controller).

Given Data / Assumptions:

• Host processor executes general-purpose code and coordinates workloads.
• Display controller manages frame buffers, rasterization, and scan-out.
• The third element should be the physical display that presents pixels.

Concept / Approach:
Visual output requires a chain: computation, driving electronics, and a viewing device. Historically, high-end workstations used CRTs as the main display unit. The generic term in classic workstation literature is CRT when referring to the display device in that era.

Step-by-Step Solution:

Verification / Alternative check:
In historical workstation configurations from the raster graphics era, documentation lists CPU, graphics controller, and CRT as canonical components. Modern displays may be LCD or OLED, but the classic term remains CRT for that configuration.

Why Other Options Are Wrong:

• digitizer: input device used for drawing, not a core display component.
• keyboard: input peripheral rather than a graphics pipeline element.
• mouse: also input and not part of the display chain.
• None of the above: incorrect because CRT is appropriate in the given workstation context.

Common Pitfalls:
Confusing input peripherals with display hardware and assuming modern flat panels invalidate the historical trio referenced in classic workstation design.

Final Answer:
CRT