The kind of thoughts that keep a person from falling asleep can arise in either half of the brain. Therefore, a person being prevented from sleeping solely by such thoughts would be able to fall asleep by closing the eyes and counting sheep, because this activity fully occupies the left half of the brain with imagining sheep, thereby excluding the sleep-preventing thoughts.
What this question is testing
Your task
Break the argument into its conclusion and evidence, then do exactly what the question stem asks with that structure.
Common trap
Answers that sound relevant to the topic but don't connect to the argument's actual reasoning.
Winning move
Predict what a right answer must do, then test each choice against the conclusion-evidence gap.
Reading along? Open the full official question in LawHub — we show a fragment here and keep the reasoning in our own words.