Music notation has made lifes easier, as it is written down in such a way that anyone can play it. Many ways were used in the past to write music. In past, the notation was written on tablets called cuneiform. Today mostly the musicians write their musical notes on stave.
The rhythm of early notated music came from the notation. The answer would be letter B. The earliest form of musical notation can be found in a cuneiform tablet that was created at Nippur. While in 1000 CE, Guido D'Arezzo made many improvements in music theory.
