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
An expansion alliance made with an expansion screw is an example of: 
Select and explain. 
A. Simple anchorage, B. Reciprocal anchorage, C. Multiple anchorage, D. Reinforced anchorage
B: Reciprocal anchorage
Answer: B: Reciprocal anchorage 
Explanation: None