This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
Aspirin acts on which part of brain? 
Select and explain. 
A. Substantia gelatinosa, B. Limbic system, C. Medulla, D. Cortex
A: Substantia gelatinosa
Answer: A: Substantia gelatinosa 
Explanation: None