The point of it is not to have you refer to any passage, but to ask you how, as a general matter, you would approach a question stem of this type.
If you are asked "which one of the following must be false," then what, in terms of "true," is the correct answer? The answer choice that "cannot be true" (which is a synonym for "must be false," written in terms of "truth").
The idea here is that it is easier to think in terms of true as opposed to in terms of false.
Watch the "True v. False" part of the Intro to Logical Reasoning video lesson for a more in-depth discussion of these concepts.
Hope this helps! Please let us know if you have any additional questions.
