OK, I think I finally got it. You want all three prompts to be optional. User can fill in only 1 prompt and still get the data.
See this FAQ about how to get ALL included in your prompt options. Then, run your report, selecting ALL for all three prompts. Publish the report that way. Then, when a user runs the report, the prompts will still have ALL in them, and the users can change the one that they want, leaving ALL in the other two.
MichaelWelter 
(BOB member since 2002-08-08)