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: Anatomy
The first bone to ossify in body is: 
Select and explain. 
A. Lower end of femur, B. Clavicle, C. Upper end of humerus, D. Upper end of tibia
B: Clavicle
Answer: B: Clavicle 
Explanation: Clavicle