Even I wasn’t sure about this, just to be on safe side I sent their birth certificates.
I think we are supposed to send the country specific docs for both country of residence and citizenship.
Also alot of people got a request later to provide Sponsor’s birth certificate + other proofs of relationship b/w sponsor & PA, from that I imagine these country specific requirement are meant for Sponsor and not for PA.
So to clear this confusion, I sent parents birth certificates as well as my BC + my adhaar card + 10th/12th certificates (these were the only docs I have).