Passage Summary: If you can't sleep because your brain is busy thinking, you can fix it by counting sheep. This works because counting uses one side of the brain and imagining sheep uses the other, so your brain is too busy to think about anything else.

Conclusion: Counting sheep allows a person to fall asleep by blocking out intrusive thoughts.

Reasoning: Sleep-preventing thoughts can occur in either the left or right hemisphere of the brain; counting sheep occupies the left hemisphere with numbers and the right hemisphere with imagery, leaving no room for those thoughts.

Analysis: The argument relies on a 'total coverage' strategy. It identifies a problem that can manifest in one of two locations (the left or right hemisphere) and proposes a solution that simultaneously occupies both locations, thereby excluding the problem. When looking for a parallel, seek an answer choice that addresses a dual-source problem by applying a solution that covers all possible avenues at once. The logic is essentially: if A or B can cause X, then occupying both A and B will prevent X.