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: Medicine
In pneumatic dilatation for the treatment of achalasia, the cylindrical balloon dilator is dilated upto: 
Select and explain. 
A. 1-2 cm, B. 2-3cm, C. 3-4 cm, D. 5-6 cm
C: 3-4 cm
Answer: C: 3-4 cm 
Explanation: The only effective therapies for achalasia are pneumatic dilatation and Heller myotomy. Pneumatic dilatation - Efficacy is 32-98%, The cylindrical balloon dilator is positioned across the LES and inflated to a diameter of 3-4 cm. The major complication is perforation Also note: The most common surgical procedure for achalasia is laparoscopic Heller myotomy, usually performed with an antireflux procedure (paial fundoplication). Ref: Harrison, Edition-18, Page-2432