I want to know the answer to the following question:
What type of evidence indicated that the C-Group spoke Afroasiatic languages of the Berber branches?
All the background I'm provided with is that "According to Peter Behrens (1981) and Marianne Bechaus-Gerst (2000), linguistic evidence indicates that the C-Group and Kerma peoples spoke Afroasiatic languages of the Berber and Cushitic branches, respectively.". Is that enough to answer the question?