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: Pathology
Which of the following is unlikely to cause enamel hypoplasia? 
Select and explain. 
A. Rickets, B. Fluoride, C. Congenital syphilis, D. Cleidocranial dysostosis
D: Cleidocranial dysostosis
Answer: D: Cleidocranial dysostosis 
Explanation: None