Apex domains cannot have CNAME records.
Question and response
Question
dig nic.dz. NS
Answer
nic.dz. 5 NS ns3.nic.dz.
nic.dz. 5 NS ns6.nic.dz.
nic.dz. 5 NS ns1.nic.dz.
nic.dz. 5 NS ns2.nic.dz.
Authority
The response has no authority records.
Additional
ns1.nic.dz. 5 A 193.194.64.242
ns2.nic.dz. 5 A 213.179.160.66
ns3.nic.dz. 5 A 193.194.73.75
ns6.nic.dz. 5 A 193.194.81.242
ns1.nic.dz. 5 AAAA 2001:4340:1030:2:0:0:0:2
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0