rc.yahoo.com has no NS records.
NS records for this zone are defined at yahoo.com.
NS records for this zone are defined at yahoo.com.
Question and response
Question
dig a7de0457831fd11f7.awsglobalaccelerator.com. NS
Answer
The response has no answer records.
Authority
awsglobalaccelerator.com. 900 SOA ns-609.awsdns-12.net. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0