Apex domains cannot have CNAME records.
Question and response
Question
dig dedicated.clara.ne.jp. NS
Answer
dedicated.clara.ne.jp. 5 NS s11.clara.co.jp.
dedicated.clara.ne.jp. 5 NS hnd.clara.co.jp.
dedicated.clara.ne.jp. 5 NS s10.clara.co.jp.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0