How did historians determine that the mayans had a written language?

Historians found an evidence called Mayan script which is the writing system of the Maya civilization. It is the only writing system that has been substantially deciphered by specialists. Hostorians completely undestood the system of Mayan wrinnet language, and now they compare its function to modern Japanese writing.

It is c because it shows how the author is stating their own oppinion about the protagonist