This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolic Disorders Leading to Osteosclerosis, Subject name: Orthopaedics
Marble bone disease is better known as? 
Select and explain. 
A. Osteoporosis, B. Osteochondritis, C. Osteopetrosis, D. Osteogenesis imperfecta
C: Osteopetrosis
Answer: C: Osteopetrosis 
Explanation: ANSWER: (C) OsteopetrosisREF: Bone diseases: macroscopic, histological, and radiological diagnosis By Claus-Peter Adler- Page 54Osteopetrosis, literally "stone bone", also known as marble bone disease and Albers-Schonbergdisease is an extremely rare inherited disorder whereby the bones harden, becoming denser due to increased calcified bone tissue, namely osteosclerosis.