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
While performing biomechanical preparation, apical constriction is enlarged to 50 sized  instrument. What would be the next step? 
Select and explain. 
A. Use reverse filing technique, B. Reinstrument with larger instrument 1 mm short of previous preparation, C. Fit a 50 mm cone and condense carefully, D. Fill with 40 sized cone
B: Reinstrument with larger instrument 1 mm short of previous preparation
Answer: B: Reinstrument with larger instrument 1 mm short of previous preparation 
Explanation: None