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
Raju, a 10 yr old child, presents with a predisposition to fractures, anaemia, hepatosplenomegaly and a diffusely increased radiographic density of bones. The most likely diagnosis is - 
Select and explain. 
A. Osteogensis imperfecta, B. Pyknodysostosis, C. Myelofibrosis, D. Osteopetrosis
D: Osteopetrosis
Answer: D: Osteopetrosis 
Explanation: Osteopetrosis is characterized by progressive anemia, hepatosplenomegaly, severe infections, pathological fractures and diffusely sclerotic bone.