While researching a topic, a student has taken the following notes:
•In music theory, the term "key" refers to the set of musical notes that forms the foundation of a piece of music.
•In On the Sensations of Tone (1863), German physicist Hermann von Helmholtz describes the moods of various musical keys.
•He describes the key of D flat major as expressing "fullness of tone."
•He describes the key of C major as "expressive of innocence."
•"Waterfalls" (1995) by TLC is a song written in D flat major.
•"Imagine" (1971) by John Lennon is a song written in C major.
The student wants to emphasize a difference between "Waterfalls" and "Imagine." Which choice most effectively uses relevant information from the notes to accomplish this goal?