Apex domains cannot have CNAME records.
Question and response
Question
dig eu.org. NS
Answer
EU.ORG. 4 NS NS.BORTZMEYER.EU.ORG.
EU.ORG. 4 NS WOMBAT.BILLAUD.EU.ORG.
EU.ORG. 4 NS HOBBES.BSD-DK.DK.
EU.ORG. 4 NS GRA.WOLFHUGEL.EU.
EU.ORG. 4 NS NS1.ERIOMEM.NET.
EU.ORG. 4 NS NS1.EU.ORG.
EU.ORG. 4 NS NS3.KELTIA.NET.
EU.ORG. 4 NS DNS.ELM.NET.
Authority
The response has no authority records.
Additional
ns.bortzmeyer.EU.ORG. 4 A 172.104.125.43
gra.wolfhugel.eu. 4 A 87.98.144.100
ns1.eu.org. 4 A 45.63.100.187
ns1.eriomem.net. 4 A 136.244.111.41
ns3.keltia.net. 4 A 108.61.167.174
wombat.billaud.eu.org. 4 A 139.99.155.59
ns.bortzmeyer.EU.ORG. 4 AAAA 2400:8902:0:0:f03c:91ff:fe69:60d3
gra.wolfhugel.eu. 4 AAAA 2001:41d0:b00:a02:0:0:0:12
ns1.eu.org. 4 AAAA 2001:19f0:7402:6b6:5400:1ff:fe9e:d9fe
ns1.eriomem.net. 4 AAAA 2a05:f480:1400:2c3f:5400:4ff:fef4:e48
ns3.keltia.net. 4 AAAA 2001:19f0:5000:84c2:0:0:0:64
wombat.billaud.eu.org. 4 AAAA 2402:1f00:8100:400:0:0:0:428
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0