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
Name the injury seen in the colour plate: 
Select and explain. 
A. Crown fracture, B. Enamel infraction, C. Crown fracture without pulp exposure, D. None
B: Enamel infraction
Answer: B: Enamel infraction 
Explanation: A crack line or chip of the enamel is the key clinical feature of enamel infarction.
ENAMEL INFARCTION
CLINICAL FINDINGS: Visual examination by DYES (Methylene Blue). Tooth is not tender on percussion. If tender on percussion, check for luxation injury/root fracture.
TREATMENT: Etching and sealing with resin to prevent discoloration of infarction line.