This statement can be supported by the paragraph.
A. Ancient Egyptian writing became more complex over time.
Explanation:
The book that is The Riddle of the Rosetta Stone by James Cross Giblin. is one of the definite guides into the study of Ancient Egyptian civilization that was undertaken by the British and this passage relates to the development of writing system that was discovered in Egypt.
This passage clearly shows that the writing system that had developed became very complex over time and had become a full writing system by the time of 2500 BCE