This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bone Dysplasia & Soft Tissue Affection, Subject name: Orthopaedics
Marble bone disease is - 
Select and explain. 
A. Osteoporosis, B. Paget's disease, C. Osteopetrosis, D. Osteogenesis imperfecta
C: Osteopetrosis
Answer: C: Osteopetrosis 
Explanation: Ans. is 'c' i.e., Osteopetrosis o Osteopetrosis is also known as Marble bone disease or Albers-Schonberg disease.o Paget's disease is known as Osteitis deformans,o Osteogenesis imperfecta is known as Brittle bone disease,o Osteoporosis is known as Fragile bone disease.