Apex domains cannot have CNAME records.
Question and response
Question
dig versions.us.com. NS
Answer
versions.us.com. 5 NS carlos.ns.cloudflare.com.
versions.us.com. 5 NS teagan.ns.cloudflare.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0