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: Radiology
Acoustic shadow on USG is due to: 
Select and explain. 
A. Reflection, B. Refraction, C. Aefact, D. Absorption of waves
A: Reflection
Answer: A: Reflection 
Explanation: Ans. Reflection