Apex domains cannot have CNAME records.
Question and response
Question
dig 201.in-addr.arpa. NS
Answer
201.in-addr.arpa. 5 NS A.LACTLD.ORG.
201.in-addr.arpa. 5 NS NS4.APNIC.NET.
201.in-addr.arpa. 5 NS LACNIC.AUTHDNS.RIPE.NET.
201.in-addr.arpa. 5 NS RIRNS.ARIN.NET.
201.in-addr.arpa. 5 NS NS3.AFRINIC.NET.
201.in-addr.arpa. 5 NS A.ARPA.DNS.BR.
201.in-addr.arpa. 5 NS NS2.LACNIC.NET.
201.in-addr.arpa. 5 NS NS4.LACNIC.NET.
201.in-addr.arpa. 5 NS NS.LACNIC.NET.
Authority
The response has no authority records.
Additional
a.lactld.org. 5 A 200.0.68.10
ns.lacnic.net. 5 A 200.3.13.10
ns2.lacnic.net. 5 A 200.3.13.11
ns3.afrinic.net. 2 A 204.61.216.100
ns4.apnic.net. 2 A 202.12.31.53
ns4.lacnic.net. 5 A 190.112.52.35
rirns.arin.net. 2 A 199.253.249.53
a.lactld.org. 5 AAAA 2801:14:a000:0:0:0:0:10
ns.lacnic.net. 5 AAAA 2001:13c7:7002:3000:0:0:0:10
ns2.lacnic.net. 5 AAAA 2001:13c7:7002:3000:0:0:0:11
ns3.afrinic.net. 2 AAAA 2001:500:14:6100:ad:0:0:1
ns4.apnic.net. 2 AAAA 2001:dd8:12:0:0:0:0:53
ns4.lacnic.net. 5 AAAA 2001:13c7:7020:210:0:0:0:35
rirns.arin.net. 2 AAAA 2620:38:2000:0:0:0:0:53
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0