What is the minimum requirement of RAM for Windows XP Professional?

What does a constrained user interface do?

A. It prevents unauthorized users from logging in. B. It limits the data visible in an interface based on the content. C. It limits the access a user is provided based on what activity they are performing. D. It limits what users can do or see based on privileges.

Most exceptions that are used by programmers derive from three C# classes. What are those classes?

What will be an ideal response?