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: Orthopaedics
[{'content': "Absent lateral 1/3rd of clavicle is seen in - \nSelect and explain. \nA. Hyperparathyroidism, B. Turner's syndrome, C. Fibrous dysplasia, D. Cleidocranial dysostosis", 'role': 'user'}, {'content': 'Answer: D \nExplanation: Cleidocranial dysostosis is a developmental affection of the skeleton in which there is deficient ossification of bones formed in the membrane.\nThe clavicle may be absent laterally, in its middle third, occasionally in its sternal third or very rarely in its entire length.', 'role': 'assistant'}]