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
The following radiograph shows: 
Select and explain. 
A. Fusion in 22, B. Gemination in 22, C. Concrescence in 22, D. Dilaceration in 21
B: Gemination in 22
Answer: B: Gemination in 22 
Explanation: Gemination
Geminated teeth are anomalies which arise from an attempt at the division of a single tooth germ by an invagination, with resultant incomplete formation of two teeth. The structure is usually one with two completely or incompletely separated crowns that have a single root and root canal. It is seen in deciduous as well as permanent dentition, and in some reported cases, appears to exhibit a hereditary tendency. It is not always possible to differentiate between gemination and a case in which there has been a fusion between a normal tooth and a supernumerary tooth.
Radiological signs
The tooth has a notched incisal margin with a confluent or partially joined pulp canal system.