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: Dental
If the calcination process occurs under pressure in a 30% calcium chloride solution or in the presence of more than 1% of sodium succinate; type of gypsum product is called: 
Select and explain. 
A. Alpha- hemihydate, B. Beta-hemihydrate, C. Modified beta hemihydrate, D. Modified alpha hemihydrate
D: Modified alpha hemihydrate
Answer: D: Modified alpha hemihydrate 
Explanation: Manufacture of high strength (α modified) stone
The gypsum is calcined by boiling it in 30% calcium chloride solution. The chlorides are then washed away or autoclaved in presence of sodium succinate 0.5%. These particles are the densest of all three types. After controlled grinding, these powders have an even higher apparent density and yield a stronger set.
Microscopically, they are cuboidal in shape.
Phillips Science of Dental Materials ed 12 pg 183