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
A decrease in which of the following parameters will shift the O2 dissociation curve to the right? 
Select and explain. 
A. pH, B. Paial pressure of CO2, C. 2,3 DPG concentration, D. Temperature
A: pH
Answer: A: pH 
Explanation: Left shift (high affinity for O2) Right shift (low affinity for O2) Temperature decrease increase 2.3-DPG decrease increase p(CO2) decrease increase p(CO) increase decrease pH (Bohr effect) increase (alkalosis) decrease (acidosis) Type of haemoglobin Fetal haemoglobin Adult haemoglobin