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
Obturation with gutta-percha cones is indicated in primary teeth only when: 
Select and explain. 
A. Canals are too wide, B. Successor is missing, C. Canals are very long but straight, D. When stainless steel crown recommended
A: Canals are too wide
Answer: A: Canals are too wide 
Explanation: None