Apex domains cannot have CNAME records.
Question and response
Question
dig alibaba.com. NS
Answer
alibaba.com. 5 NS ns2.alibabadns.com.
alibaba.com. 5 NS ns1.alibabadns.com.
Authority
The response has no authority records.
Additional
ns1.alibabadns.com. 5 A 47.88.74.38
ns1.alibabadns.com. 5 A 47.241.207.18
ns1.alibabadns.com. 5 A 106.11.35.19
ns1.alibabadns.com. 5 A 106.11.41.157
ns1.alibabadns.com. 5 A 140.205.103.192
ns1.alibabadns.com. 5 A 140.205.122.66
ns2.alibabadns.com. 5 A 47.88.74.36
ns2.alibabadns.com. 5 A 47.241.207.16
ns2.alibabadns.com. 5 A 106.11.35.18
ns2.alibabadns.com. 5 A 106.11.41.158
ns2.alibabadns.com. 5 A 140.205.103.194
ns2.alibabadns.com. 5 A 140.205.122.77
ns1.alibabadns.com. 5 AAAA 2401:b180:4100:0:0:0:0:1
ns2.alibabadns.com. 5 AAAA 2401:b180:4100:0:0:0:0:2
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0