Apex domains cannot have CNAME records.
Question and response
Question
dig host.md. NS
Answer
host.md. 5 NS ns1.host.md.
host.md. 5 NS ns2.host.md.
Authority
The response has no authority records.
Additional
ns1.host.md. 5 A 217.26.150.10
ns2.host.md. 5 A 217.26.150.12
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0