Context: Two of the earliest dialectal divisions among Iranian indeed happen to not follow the later division into Western and Eastern blocks. These concern the fate of the Proto-Indo-Iranian first-series palatal consonants, *ć and *dź:

Question: What elements of Proto-Indo-Iranian did not diverge according to the ensuing split between eastern and western variants?
Answer: *ć and *dź

Question: What type of letters are *ć and *dź?
Answer: first-series palatal consonants

Question: What Iranian dialects did not follow the Western and Eastern blocks?
Answer: Unanswerable

Question: What type of valves are c and dz?
Answer: Unanswerable