Apex domains cannot have CNAME records.
Question and response
Question
dig tac.net. NS
Answer
tac.net. 1 NS dns2.cidc.telus.com.
tac.net. 1 NS dns1.cidc.telus.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0