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
Developmental depressions on both mesial and distal sides of roots are seen in: 
Select and explain. 
A. Mandibular central incisor, B. Maxillary canines, C. Mesial root of mandibular 1st molar, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: Deep concavities on distal surface are present in – Maxillary 1st premolar
Deep concavities on distal surface are present in – Maxillary 1st molar
Developmental depressions on both mesial and distal sides of roots are seen in – Mandibular central incisors, upper canines, mesial root of mandibular 1st molar.