Rhythm is an ordered repetition of strong and weak elements at regular or irregular intervals. what does rhythm in a pattern indicate?
a. symmetry
b. motion
c. harmony

Rhythm is a combination of repeated elements with slight variations in the pattern. This represents movement and motion within art, and is a technique used by visual arts and designers to create fluidity within an artwork or object. Pattern and repetition are commonly used by artists to create this effect.

The gregorian chant was a major cultural milestone in the middle ages. it was one of the first codified forms of music meant to be played as written, where previously it was difficult to mass-produce and disseminate any music. what's more, these chants were also some of the first examples of musical notation: the notes and bars of today's music sheets are a reflection of centuries of evolution beginning with these chants. it became official throughout the entirety of the catholic church, meaning that nearly all of europe followed this musical notation and styling.

It's your  third option or c