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
That part of the mind which is working on reality principle is - 
Select and explain. 
A. ID, B. Ego, C. Super ego, D. Ego-ideal
B: Ego
Answer: B: Ego 
Explanation: The id  → Pleasure principle
The Ego  → Reality principle
The superego → Idealism principle