Apex domains cannot have CNAME records.
Question and response
Question
dig arpah.gov. NS
Answer
arpah.gov. 5 NS a22-64.akam.net.
arpah.gov. 5 NS a11-66.akam.net.
arpah.gov. 5 NS a1-32.akam.net.
arpah.gov. 5 NS a7-64.akam.net.
arpah.gov. 5 NS a12-65.akam.net.
arpah.gov. 5 NS a14-65.akam.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0