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: Pathology
Two siblings were diagnosed with Osteogenesis imperfecta. But their parents are normal. Mechanism of inheritance is: 
Select and explain. 
A. Anticipation, B. Genomic imprinting, C. Germ line mosaicism, D. New mutation
C: Germ line mosaicism
Answer: C: Germ line mosaicism 
Explanation: . Germ line mosaicism