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