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
Diameter of sprue should be: 
Select and explain. 
A. Equal to the thickest portion of wax pattern., B. Half to the thickest portion of wax pattern., C. Double to the thickest portion of wax pattern., D. None of the above.
A: Equal to the thickest portion of wax pattern.
Answer: A: Equal to the thickest portion of wax pattern. 
Explanation: None