Apex domains cannot have CNAME records.
Question and response
Question
dig monster.com. NS
Answer
monster.com. 5 NS ns2.tmpw.net.
monster.com. 5 NS ns1.tmpw.net.
Authority
The response has no authority records.
Additional
ns1.tmpw.net. 5 A 208.71.193.234
ns2.tmpw.net. 5 A 208.71.199.234
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0