Apex domains cannot have CNAME records.
Question and response
Question
dig ucdavis.edu. NS
Answer
ucdavis.edu. 5 NS ns0105.secondary.cloudflare.com.
ucdavis.edu. 5 NS ns0229.secondary.cloudflare.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0