The limits of the vertical visual field indicate that displays should be positioned where in...

For optimal viewing comfort, the top of a display should not be positioned more than 30 degrees above the viewer’s line of sight. This guideline ensures that viewers do not have to strain their necks to see the entire screen. While Options A and B might seem reasonable, 30 degrees is considered the upper limit for comfortable viewing, with viewers ideally positioned to see the full display without needing to look up excessively.

CTS References: AVIXA CTS Exam Guide, Chapter on Display Mounting and Viewing Angles; CTS Handbook, Section on Ergonomic Viewing Considerations.