This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pharmacology
Chemically, Plaster of Paris (POP) is 
Select and explain. 
A. Calcium carbonate, B. Calcium sulphate, C. Anhydrous calcium sulphate, D. Hemihydrous calcium sulphate
D: Hemihydrous calcium sulphate
Answer: D: Hemihydrous calcium sulphate 
Explanation: chemical name is calcium sulfhate hemihydrate , called plaster of paris since obtained from gypsum in paris.