What is the best solution to validate an email address using regular expressions and some sophisticated logic?

You have to validate an email address using regular expressions and some sophisticated logic, What is the best solution?

A.
Create a user defined function in CLR assembly

B.
Create a stored procedure

C.
Create a trigger

D.
use email datatype

Explanation:
http://msdn.microsoft.com/en-us/library/ms186755.aspx

http://www.mssqltips.com/tip.asp?tip=1672

http://msdn.microsoft.com/en-us/magazine/cc163473.aspx