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
A radiolucent root canal suddenly disappears at the mid root portion, the most probable diagnosis is 
Select and explain. 
A. Calcifications within the pulp, B. Bifurcation of the canal, C. Sclerosis of the adjacent bone, D. Ankylosis
B: Bifurcation of the canal
Answer: B: Bifurcation of the canal 
Explanation: None