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 most common error seen during access cavity preparation of maxillary and mandibular incisors is: 
Select and explain. 
A. Perforation of the lingual or labial walls, B. Gouging of pulpal contents, C. Tooth fracture, D. All of the above
A: Perforation of the lingual or labial walls
Answer: A: Perforation of the lingual or labial walls 
Explanation: None