; Audi A6 1st Gen (C4/4A)* Original radio options - InCarTec

There are multiple original radio options in the Audi A6 1st Gen (C4/4A)*, which option is the original fitted system?

Audi Concert Audi Concert
Audi Concert I CD Audi Concert I CD
Audi Delta Audi Delta
Audi Delta BOSE Audi Delta BOSE