How do I add null exception to regex statement C#
<p>How do I add the exception of null or allow the value null to the following regex statement?</p>

<p>@"^[a-zA-Z0-9]\d{2}a-zA-Z0-9{2}[A-Za-z0-9]$|[^\x00-\x80]|\b\w{1,1}\b";</p>