Apex domains cannot have CNAME records.
Question and response
Question
dig PC-NET.RU. NS
Answer
pc-net.ru. 1 NS ns2.pc-net.ru.
pc-net.ru. 1 NS ns.pc-net.ru.
Authority
The response has no authority records.
Additional
ns.pc-net.ru. 1 A 212.164.86.69
ns2.pc-net.RU. 1 A 80.69.184.161
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0