Which cultural element was common to all greek city-states?

a. art

b. government

c. alphabet

d. music

The correct answer is C. alphabet

Most of them used the same alphabet which has gone almost unchanged up until the modern age. That's why common things in modern greek sound sometimes familiar from things like sayings or anything similar.

Musical notation is a system which is used to  visually represent music  pertaining to the ear  contend  with instruments or sung by the human voice through  the employment  of written, printed, or different symbols.in the western music tradition, the sound is represented in written form through musical notation.in musical notation, the pitch is indicated exclusively by the position of notes on the lines and spaces of the staff.