What is wrong with C? This is a GmatPrep question.

During the same period in which the Maya were developing a hieroglyphic system of writing, the Aztec people also developed a written language, but it was not as highly sophisticated as that of the Maya and was more pictographic in nature.

A. but it was not as highly sophisticated as that of the Maya and was

B. but it was not as highly sophisticated ad the Maya, being

C. but, not as highly sophisticated as the Maya's, was

D. not as highly sophisticated as that of the Maya, however, being

E. not as highly sophisticated as the Maya's however, it was