What does the term 'diatonic' indicate?

The term 'diatonic' indicates a system that is grounded in the natural major and minor scales, meaning that it primarily utilizes the notes that are found within these scales without any alterations like sharps or flats beyond those that are normally part of the key signature. When a piece of music is described as diatonic, it suggests that the harmonies, melodies, and the overall structure conform to the seven notes of a specific key, thereby aligning with the traditional Western tonal system.

The word 'diatonic' fundamentally contrasts with the chromatic scale, which involves the use of all twelve pitches available in Western music, including sharps and flats. Instead, being diatonic signifies a return to simplicity and consonance inherent in major and minor tonalities. This makes it clear why option B is the appropriate choice, as it captures the essence of scales that are strictly within the confines of major and minor keys without venturing into chromaticism or modes that deviate from these traditional structures.