What is unique about the Whole-Tone Scale?

The Whole-Tone Scale is distinct because it consists exclusively of whole steps separating each note. This results in a scale that lacks the typical half steps found in diatonic scales. Each note in the Whole-Tone Scale is spaced equally, creating a dreamy and ambiguous sound that is quite different from the more conventional scales. This characteristic of being based solely on whole steps leads to the conclusion that there are only six unique notes in the scale before it repeats, distinguishing it from other scales that are built on a mixture of whole and half steps.

In terms of the other options, half steps only would reflect a different scale, while stating that it includes all notes in an octave misrepresents its structure, as the Whole-Tone Scale does not encompass every note within an octave. Additionally, claiming that it is a five-note scale would misidentify it, since a Whole-Tone Scale contains six notes. Therefore, the uniqueness of the Whole-Tone Scale lies in the exclusive use of whole steps.