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
Best method to evaluate bone defect is 
Select and explain. 
A. Sounding, B. IOPA, C. Bitewing radiograph, D. Use of florid probes
A: Sounding
Answer: A: Sounding 
Explanation: Transgingival probing is known as sounding.