Apex domains cannot have CNAME records.
Question and response
Question
dig guru. NS
Answer
guru. 5 NS v0n1.nic.guru.
guru. 5 NS v0n3.nic.guru.
guru. 5 NS v2n1.nic.guru.
guru. 5 NS v2n0.nic.guru.
guru. 5 NS v0n2.nic.guru.
guru. 5 NS v0n0.nic.guru.
Authority
The response has no authority records.
Additional
v0n0.nic.guru. 94551 A 65.22.28.36
v0n1.nic.guru. 89922 A 65.22.29.36
v0n2.nic.guru. 105652 A 65.22.30.36
v0n3.nic.guru. 94551 A 161.232.14.36
v2n0.nic.guru. 99678 A 65.22.31.36
v2n1.nic.guru. 99678 A 161.232.15.36
v0n0.nic.guru. 94551 AAAA 2a01:8840:1e:0:0:0:0:36
v0n1.nic.guru. 89922 AAAA 2a01:8840:1f:0:0:0:0:36
v0n2.nic.guru. 105652 AAAA 2a01:8840:20:0:0:0:0:36
v0n3.nic.guru. 94551 AAAA 2a01:8840:f8:0:0:0:0:36
v2n0.nic.guru. 99678 AAAA 2a01:8840:21:0:0:0:0:36
v2n1.nic.guru. 99678 AAAA 2a01:8840:f9:0:0:0:0:36
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0