Apex domains cannot have CNAME records.
Question and response
Question
dig vsnl.net.in. NS
Answer
vsnl.net.in. 4 NS inpudiidnsprprd01.tatacommunications.com.
vsnl.net.in. 4 NS inchvsidnsseprd01.tatacommunications.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0