Answer: B. the source of memories
Explanation: In "Exhalation" by Ted Chiang, what the narrator hopes to discover by auto-dissecting his own brain is the source of memories. The narrator wants to know how memories are stored in their brains. The story takes place in a world inhabited by pneumatically-powered machine men. They go to argon stations to refill their lungs. The narrator, a scientist, dissects his own brain to discover where memories are stored. He finds out that the memory function does not work in tandem with gears, but instead is air, argon. Memories are stored in argon. Air is essential to their lives, and so is air pressure.