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
The difficulty in adopting a stainless steel crown to a
primary mandibular first molar is. 
Select and explain. 
A. Wide bucco lingual contact, B. Buccal cervical ridge showing constriction, C. Prominent oblique ridge, D. All of the above
B: Buccal cervical ridge showing constriction
Answer: B: Buccal cervical ridge showing constriction 
Explanation: None