Answer: C. Underlying pulse of a piece of music.
Examples:
Music written for a marching band may have a signature of 4/4, which means that four quarter-notes are specified n each bar.
On the other hand, music written for waltzing may have a signature of 3/4, which means that three quarter-notes are specified for each bar.
A metronome is often used during music lessons to teach the student how to observe the number of beats in a bar.
