Which Index A Table Is Using In T-sql 2000

On one of those common interview question lists, there is the question:

How do you know which index a table is using?

The two answers that I've found are:

SELECT * FROM user_constraints
--and
SELECT TableName,IndexName FROM user_constraints

Both of these return the error:

Server: Msg 208, Level 16, State 1, Line 1
Invalid object name 'user_constraints'.

Is this because I'm using the free version of 2000(MSDE)?
If so, what is the right answer for this version?

-Thanks