Apex domains cannot have CNAME records.
Question and response
Question
dig nfbnet.org. NS
Answer
nfbnet.org. 5 NS pdns03.domaincontrol.com.
nfbnet.org. 5 NS pdns04.domaincontrol.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0