Apex domains cannot have CNAME records.
Question and response
Question
dig webfile.jp. NS
Answer
webfile.jp. 2 NS ns02.key-p.co.jp.
webfile.jp. 2 NS ns01.key-p.co.jp.
Authority
The response has no authority records.
Additional
ns01.key-p.co.jp. 2 A 121.83.217.174
ns02.key-p.co.jp. 2 A 122.218.100.83
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0