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': 'Increased density in skull vault is seen in -a) Hyperparathyroidismb)  Multiple myelomac) Fluorosisd) Renal osteodystrophy \nSelect and explain. \nA. acd, B. ad, C. bc, D. bde', 'role': 'user'}, {'content': 'Answer: A \nExplanation: All the causes of generalized increased in bone density can cause increased density of skull vault — Practical imaging 2nd /e 73\nFluorosis and secondary hyperparathyroidism (renal osteodystrophy) cause increased density of skull vault.', 'role': 'assistant'}]