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: Psychiatry
Delusion is a disorder of- 
Select and explain. 
A. Thought, B. Perception, C. Insight, D. Cognition
A: Thought
Answer: A: Thought 
Explanation: Delusion is a disorder of content of thought.