Apex domains cannot have CNAME records.
Question and response
Question
dig mufg.jp. NS
Answer
mufg.jp. 5 NS a16-64.akam.net.
mufg.jp. 5 NS a11-67.akam.net.
mufg.jp. 5 NS a5-66.akam.net.
mufg.jp. 5 NS ns004-ar0tb4rec1f4c1mj.a.d-53.net.
mufg.jp. 5 NS a8-67.akam.net.
mufg.jp. 5 NS a1-10.akam.net.
mufg.jp. 5 NS a26-65.akam.net.
mufg.jp. 5 NS ns004-ar0tb4rec1f4c1mj.a.d-53.jp.
mufg.jp. 5 NS ns004-ar0tb4rec1f4c1mj.a.d-53.info.
Authority
The response has no authority records.
Additional
a11-67.akam.net. 2 A 84.53.139.67
a11-67.akam.net. 2 AAAA 2600:1480:1:0:0:0:0:43
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0