Which of the following statements is true? fretboard diagrams are always chord diagrams. fretboard diagrams can be oriented vertically or horizontally. fretboard diagrams can only be oriented horizontally. fretboard diagrams can only be oriented vertically.

The frets could be somewhere alongside the neck. Some diagrams are in favor of vertically oriented, rather than horizontally. But they function the same way, just turn it 90 degrees clockwise. So, the answer is fretboard diagrams can be oriented vertically or horizontally.