Apex domains cannot have CNAME records.
Question and response
Question
dig egghead-corp.com. NS
Answer
egghead-corp.com. 5 NS olivia.ns.cloudflare.com.
egghead-corp.com. 5 NS yadiel.ns.cloudflare.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0