Apex domains cannot have CNAME records.
Question and response
Question
dig ucsc.edu. NS
Answer
ucsc.edu. 3 NS adns1.ucsc.edu.
ucsc.edu. 3 NS ns.zocalo.net.
ucsc.edu. 3 NS adns2.ucsc.edu.
Authority
The response has no authority records.
Additional
adns1.ucsc.edu. 3 A 128.114.100.100
adns2.ucsc.edu. 3 A 128.114.100.200
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0