Should finding truth be a process of elimination? To quote CYP on this, that's not exactly a ringing endorsement!
The fallacy in this type of reasoning is this.
Rule 1: The WTS provides a version of "Truth" that is unique.
Rule 2: You must become completely convinced that their version of reality is Truth.
Rule 3: If you doubt that the WTS is the sole provider of "Truth", see Rule 1
You can look into Christadelphian beliefs, Bible Student beliefs, Armstrong sect beleifs to expand the person's awareness, however.