question 7\nharmony is\na the main tune of a musical work, with notes played one at a time.\nb durations of…

question 7\nharmony is\na the main tune of a musical work, with notes played one at a time.\nb durations of sound that are played in relation to a beat.\nc the sound of two or more pitches performed at the same time.\nd the speed of the beat in music.
Answer
Brief Explanations:
Harmony in music refers to the combination of different pitches sounded simultaneously. Option A describes melody, option B describes rhythm - related durations, and option D describes tempo.
Answer:
C. The sound of two or more pitches performed at the same time.