Apex domains cannot have CNAME records.
Question and response
Question
dig yahbooks.com. NS
Answer
yahbooks.com. 5 NS ns-1674.awsdns-17.co.uk.
yahbooks.com. 5 NS ns-714.awsdns-25.net.
yahbooks.com. 5 NS ns-175.awsdns-21.com.
yahbooks.com. 5 NS ns-189.awsdns-23.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0