Apex domains cannot have CNAME records.
Question and response
Question
dig ink. NS
Answer
ink. 5 NS x.nic.ink.
ink. 5 NS b.nic.ink.
ink. 5 NS z.nic.ink.
ink. 5 NS a.nic.ink.
ink. 5 NS c.nic.ink.
ink. 5 NS y.nic.ink.
Authority
The response has no authority records.
Additional
a.nic.ink. 98692 A 37.209.192.10
b.nic.ink. 98692 A 37.209.194.10
c.nic.ink. 98692 A 37.209.196.10
x.nic.ink. 98692 A 156.154.172.82
y.nic.ink. 98692 A 156.154.173.82
z.nic.ink. 98692 A 156.154.174.82
a.nic.ink. 98692 AAAA 2001:dcd:1:0:0:0:0:10
b.nic.ink. 98692 AAAA 2001:dcd:2:0:0:0:0:10
c.nic.ink. 98692 AAAA 2001:dcd:3:0:0:0:0:10
x.nic.ink. 98692 AAAA 2610:a1:1074:0:0:0:1:82
y.nic.ink. 98692 AAAA 2610:a1:1075:0:0:0:1:82
z.nic.ink. 98692 AAAA 2610:a1:1076:0:0:0:1:82
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0