Apex domains cannot have CNAME records.
Question and response
Question
dig 200.110.124.in-addr.arpa. NS
Answer
200.110.124.in-addr.arpa. 5 NS ns-1560.awsdns-03.co.uk.
200.110.124.in-addr.arpa. 5 NS ns-714.awsdns-25.net.
200.110.124.in-addr.arpa. 5 NS ns-180.awsdns-22.com.
200.110.124.in-addr.arpa. 5 NS ns-1221.awsdns-24.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0