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: Dental
Latest technique by which bone graft is obtained without
damaging vital structure, vessels/veins is based on? 
Select and explain. 
A. Piezoelectric vibration, B. Osteotome, C. Ultrasonic/soft lasers, D. Electrocautery
A: Piezoelectric vibration
Answer: A: Piezoelectric vibration 
Explanation: None