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
Interaction of histamine with  H2 receptor in parietal cell results in 
Select and explain. 
A. Increase in intracellular Na+ concentration, B. Increase in intracellular CAMP production, C. Increase in intracellular Ca2+ concentration, D. Stimulates IP3 - DAG pathway
B: Increase in intracellular CAMP production
Answer: B: Increase in intracellular CAMP production 
Explanation: None