Apex domains cannot have CNAME records.
Question and response
Question
dig a.d-53.jp. NS
Answer
a.d-53.jp. 1 NS ns.iij-dns.net.
a.d-53.jp. 1 NS ns.iij-dns.jp.
a.d-53.jp. 1 NS ns.iij-dns.biz.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0