After navigating to Configuration > Dial plan > Transforms on a Cisco TelePresence VCS, you see a transform
of type Regex with the following pattern:
([^@]*)
Which of the following will be matched by the transform?

A.
nothing

B.
anything

C.
anything that contains an @ symbol

D.
anything that does not contain an @ symbol

E.
anything that contains the characters ^@

F.
anything that contains the characters ([^@]*)

Explanation:
Anything that does not contain an @ symbol will be matched by the transform. Transforms can be used to
modify an alias. Each transform can be set to match an exact string, a prefix, a suffix, or a regular expression,
also known as a regex. If a match is made, the alias is modified.
A transform with the type set to Regex will attempt to match the pattern based on regular expression
characters. The most common regular expression characters are listed in the following table:

Therefore, the regular expression ([^@]*) will match anything that does not contain an @ symbol. You might
want to find aliases that do not contain @ symbols in order to append an @domain suffix to the alias, thereby
ensuring that H.323 calls and Session Initiation Protocol (SIP) calls both use the same SIP Uniform Resource
Identifier (URI).

Cisco: Cisco TelePresence Video Communication Server, Administrator Guide, Software version: X8.1:
Transforms for alphanumeric H.323 ID dial strings (PDF)
Cisco: Cisco TelePresence Video Communication Server, Administrator Guide, Software version: X8.1:
Regular Expressions (PDF)