Apex domains cannot have CNAME records.
Question and response
Question
dig HU.EU.ORG. NS
Answer
HU.EU.ORG. 5 NS hobbes.bsd-dk.dk.
HU.EU.ORG. 5 NS ns1.EU.ORG.
HU.EU.ORG. 5 NS ns.ankh.fr.EU.ORG.
HU.EU.ORG. 5 NS ns1.eriomem.net.
Authority
The response has no authority records.
Additional
NS.ANKH.FR.EU.ORG. 1 A 108.61.198.35
ns1.eu.org. 1 A 45.63.100.187
ns1.eriomem.net. 4 A 136.244.111.41
hobbes.bsd-dk.dk. 4 A 185.59.228.110
NS.ANKH.FR.EU.ORG. 1 AAAA 2001:19f0:5001:5d:5400:ff:fe4c:714f
ns1.eu.org. 1 AAAA 2001:19f0:7402:6b6:5400:1ff:fe9e:d9fe
ns1.eriomem.net. 4 AAAA 2a05:f480:1400:2c3f:5400:4ff:fef4:e48
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0