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
A 7-year-old has a 4-mm maxillary midline diastema. Which of the following should be done? 
Select and explain. 
A. Brackets should be placed to close it., B. A radiograph should be taken to rule out the presence of a supernumerary tooth., C. Nothing should be done. It will close on its own., D. Nothing should be done. Treatment should be deferred until the rest of the permanent dentition erupts.
B: A radiograph should be taken to rule out the presence of a supernumerary tooth.
Answer: B: A radiograph should be taken to rule out the presence of a supernumerary tooth. 
Explanation: When a large diastema greater than 2 mm is present, it will probably not close on its own. Diagnostic tests, such as a radiograph, should be accomplished to rule out the presence of a supernumerary tooth, usually a mesiodens.