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: Physiology
Oxygen dissociation curve shifts to right in: 
Select and explain. 
A. Hyperkalemia, B. Hypokalemia, C. Metabolic alkalosis, D. Anemia
D: Anemia
Answer: D: Anemia 
Explanation: Anemia