Apex domains cannot have CNAME records.
Question and response
Question
dig mpls.qwest.net. NS
Answer
mpls.qwest.net. 5 NS authns2.qwest.net.
mpls.qwest.net. 5 NS authns1.qwest.net.
Authority
The response has no authority records.
Additional
authns1.qwest.net. 5 A 63.150.72.4
authns2.qwest.net. 5 A 208.44.130.120
authns1.qwest.net. 5 AAAA 2001:428:0:0:0:0:0:5
authns2.qwest.net. 5 AAAA 2001:428:0:0:0:0:0:6
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0