Apex domains cannot have CNAME records.
Question and response
Question
dig dc.net.tr. NS
Answer
dc.net.tr. 5 NS dns2.dc.net.tr.
dc.net.tr. 5 NS dns1.dc.net.tr.
dc.net.tr. 5 NS ns1.dcner.tr.
dc.net.tr. 5 NS ns2.dcner.tr.
Authority
The response has no authority records.
Additional
dns1.dc.net.tr. 5 A 188.132.235.5
dns2.dc.net.tr. 5 A 188.132.235.5
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0