This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Medicine
Hypercalcemia is diagnosed by 
Select and explain. 
A. Ionised calcium level, B. Serum calcium, C. Serum phosphate, D. Urinary calcium concentration
B: Serum calcium
Answer: B: Serum calcium 
Explanation: (B) Serum calcium # Approach to medical treatment of hypercalcemia varies with its severity> Mild hypercalcemia,<3.0 mmol/L (12 mg/dL), can be managed by hydration.> More severe hypercalcemia must be managed aggressively;