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: Pathology
Serum marker of rickets is 
Select and explain. 
A. Acid phosphates, B. Alkaline phosphatase, C. Decreased serum calcium, D. Urinary posphates
B: Alkaline phosphatase
Answer: B: Alkaline phosphatase 
Explanation: Amongst the given options, alkaline phosphatase is best because it is raised in all type of rickets.
The primary (Basic) investigations in a child of rickets are :-


Serum calcium
Serum phosphorus
Alkaline phosphatase


If the patient does not respond to calcium and Vit D therapy, secondary investigations are done:-


Vit D level
Serum PTH
Urinary calcium and phosphorus.