Apex domains cannot have CNAME records.
Question and response
Question
dig nic.sbs. NS
Answer
nic.sbs. 5 NS d.nic.sbs.
nic.sbs. 5 NS b.nic.sbs.
nic.sbs. 5 NS a.nic.sbs.
nic.sbs. 5 NS c.nic.sbs.
Authority
The response has no authority records.
Additional
a.nic.sbs. 53749 A 194.169.218.127
b.nic.sbs. 53749 A 185.24.64.127
c.nic.sbs. 53749 A 212.18.248.127
d.nic.sbs. 53749 A 212.18.249.127
a.nic.sbs. 53749 AAAA 2001:67c:13cc:0:0:0:1:127
b.nic.sbs. 53749 AAAA 2a04:2b00:13cc:0:0:0:1:127
c.nic.sbs. 53749 AAAA 2a04:2b00:13ee:0:0:0:0:127
d.nic.sbs. 53749 AAAA 2a04:2b00:13ff:0:0:0:0:127
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0