Apex domains cannot have CNAME records.
Question and response
Question
dig 97.192.193.in-addr.arpa. NS
Answer
97.192.193.in-addr.arpa. 5 NS ns.turk.net.
97.192.193.in-addr.arpa. 5 NS ns.turknet.net.tr.
97.192.193.in-addr.arpa. 5 NS ns.turknet.io.
Authority
The response has no authority records.
Additional
ns.turk.net. 5 A 193.192.100.10
ns.turknet.io. 5 A 20.229.126.11
ns.turknet.net.tr. 5 A 212.154.100.10
ns.turk.net. 5 AAAA 2a02:ff0:2:328:193:192:100:10
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0