c. Most examples were done on vellum and were very colorful.
This statement is not true of Early Byzantine art. While vellum and colorful manuscripts, particularly in the form of illuminated manuscripts, were indeed used in some early Christian contexts, Early Byzantine art is more characterized by its mosaics and frescoes, which were often more subdued in color than the vibrant illustrated manuscripts of later periods. The vibrant and colorful style is more associated with later Byzantine art and the development of illuminated manuscripts during the Middle Ages.