Apex domains cannot have CNAME records.
Question and response
Question
dig visa.com. NS
Answer
visa.com. 5 NS melinda.ns.cloudflare.com.
visa.com. 5 NS a9-64.akam.net.
visa.com. 5 NS a2-65.akam.net.
visa.com. 5 NS lloyd.ns.cloudflare.com.
visa.com. 5 NS a1-190.akam.net.
visa.com. 5 NS a10-64.akam.net.
Authority
The response has no authority records.
Additional
a2-65.akam.net. 2 A 95.100.174.65
a9-64.akam.net. 2 A 184.85.248.64
a1-190.akam.net. 2 A 193.108.91.190
a10-64.akam.net. 2 A 96.7.50.64
a2-65.akam.net. 2 AAAA 2600:1480:7000:0:0:0:0:41
a9-64.akam.net. 2 AAAA 2a02:26f0:117:0:0:0:0:40
a1-190.akam.net. 2 AAAA 2600:1401:2:0:0:0:0:be
a10-64.akam.net. 2 AAAA 2600:1480:d000:0:0:0:0:40
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0