Apex domains cannot have CNAME records.
Question and response
Question
dig timberdoodle.com. NS
Answer
timberdoodle.com. 5 NS ns2.domain.com.
timberdoodle.com. 5 NS ns1.domain.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0