Apex domains cannot have CNAME records.
Question and response
Question
dig bet. NS
Answer
bet. 5 NS c0.nic.bet.
bet. 5 NS a0.nic.bet.
bet. 5 NS a2.nic.bet.
bet. 5 NS b0.nic.bet.
Authority
The response has no authority records.
Additional
a0.nic.bet. 1860 A 65.22.36.17
a2.nic.bet. 1860 A 65.22.39.17
b0.nic.bet. 1860 A 65.22.37.17
c0.nic.bet. 1860 A 65.22.38.17
a0.nic.bet. 1860 AAAA 2a01:8840:26:0:0:0:0:17
a2.nic.bet. 1860 AAAA 2a01:8840:29:0:0:0:0:17
b0.nic.bet. 1860 AAAA 2a01:8840:27:0:0:0:0:17
c0.nic.bet. 1860 AAAA 2a01:8840:28:0:0:0:0:17
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0