Apex domains cannot have CNAME records.
Question and response
Question
dig world. NS
Answer
world. 5 NS v0n0.nic.world.
world. 5 NS v0n2.nic.world.
world. 5 NS v0n1.nic.world.
world. 5 NS v0n3.nic.world.
world. 5 NS v2n0.nic.world.
world. 5 NS v2n1.nic.world.
Authority
The response has no authority records.
Additional
v0n0.nic.world. 160442 A 65.22.24.1
v0n1.nic.world. 160442 A 65.22.25.1
v0n2.nic.world. 140493 A 65.22.26.1
v0n3.nic.world. 160442 A 161.232.12.1
v2n0.nic.world. 160442 A 65.22.27.1
v2n1.nic.world. 140493 A 161.232.13.1
v0n0.nic.world. 160442 AAAA 2a01:8840:1a:0:0:0:0:1
v0n1.nic.world. 160442 AAAA 2a01:8840:1b:0:0:0:0:1
v0n2.nic.world. 140493 AAAA 2a01:8840:1c:0:0:0:0:1
v0n3.nic.world. 160442 AAAA 2a01:8840:f6:0:0:0:0:1
v2n0.nic.world. 160442 AAAA 2a01:8840:1d:0:0:0:0:1
v2n1.nic.world. 140493 AAAA 2a01:8840:f7:0:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0