Apex domains cannot have CNAME records.
Question and response
Question
dig bit.nl. NS
Answer
bit.nl. 3 NS nsauth3.bit.org.
bit.nl. 3 NS nsauth1.bit.nl.
bit.nl. 3 NS nsauth2.bit.nl.
Authority
The response has no authority records.
Additional
nsauth1.bit.nl. 3 A 213.136.12.51
nsauth2.bit.nl. 3 A 213.136.12.59
nsauth1.bit.nl. 3 AAAA 2001:7b8:3:2c:0:0:0:53
nsauth2.bit.nl. 3 AAAA 2001:7b8:3:2d:0:0:0:53
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0