The Extension Mechanisms for DNS (EDNS0) header bit is now required to support larger DNS message sizes for which of these reasons?
A.
to allow walking of the Resource Record Signature (RRSIG) for a domain name space
B.
to ensure that the authority section is always present
C.
to enable lookup for IPv6 AAAA records
D.
to enable lookup for DNSSEC resource records
E.
to provide a place for TXT resource records larger than 900 bytes