Apex domains cannot have CNAME records.
Question and response
Question
dig ag. NS
Answer
ag. 5 NS b0.cctld.afilias-nst.org.
ag. 5 NS d0.cctld.afilias-nst.org.
ag. 5 NS a0.cctld.afilias-nst.info.
ag. 5 NS a2.cctld.afilias-nst.info.
ag. 5 NS c0.cctld.afilias-nst.info.
ag. 5 NS b2.cctld.afilias-nst.org.
Authority
The response has no authority records.
Additional
a0.cctld.afilias-nst.info. 4 A 199.254.59.1
b0.cctld.afilias-nst.org. 4 A 199.254.60.1
c0.cctld.afilias-nst.info. 4 A 199.254.61.1
d0.cctld.afilias-nst.org. 4 A 199.254.62.1
a0.cctld.afilias-nst.info. 4 AAAA 2001:500:25:0:0:0:0:1
b0.cctld.afilias-nst.org. 4 AAAA 2001:500:26:0:0:0:0:1
c0.cctld.afilias-nst.info. 4 AAAA 2001:500:27:0:0:0:0:1
d0.cctld.afilias-nst.org. 4 AAAA 2001:500:28:0:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0