Apex domains cannot have CNAME records.
Question and response
Question
dig wbst.jp. NS
Answer
wbst.jp. 5 NS ns-616.awsdns-13.net.
wbst.jp. 5 NS ns-1289.awsdns-33.org.
wbst.jp. 5 NS ns-1557.awsdns-02.co.uk.
wbst.jp. 5 NS ns-207.awsdns-25.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0