Apex domains cannot have CNAME records.
Question and response
Question
dig gte.net. NS
Answer
gte.net. 4 NS ns1.verizon.net.
gte.net. 4 NS ns3.verizon.net.
gte.net. 4 NS ns2.verizon.net.
gte.net. 4 NS ns4.verizon.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0