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: Radiology
Interpret the developmental anomaly shown in the following radiograph: 
Select and explain. 
A. Dens invaginatus, B. Regional odontodysplasia, C. Dentinal dysplasia, D. Dentinogenesis imperfecta
A: Dens invaginatus
Answer: A: Dens invaginatus 
Explanation: Dens invaginatus
This anomaly is the result of an infolding of the enamel organ prior to calcification and represents, in its coronal form, an accentuation of the cingulum pit. The anomaly is believed to be genetically determined and has a prevalence of 5%. The maxillary lateral incisors are commonly affected. The condition rarely occurs in the deciduous dentition.
Radiological signs
The invagination appears as a linear radiopacity at the level of the cingulum. It varies in the degree that it involves the coronal tooth tissue. The tooth may display an open apex and periapical radiolucency as a sequel to loss of pulp vitality.
Ref: Interpreting Dental Radiographs by Keith Horner, Jon Rout and Vivian E Rushton