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
Maryland bridge is 
Select and explain. 
A. Cast perforated resin retained FPD, B. Etched cast resin retained FPD, C. Macroscopic mechanical retention resin retained FPD, D. Chemical bonding resin retained FPD
B: Etched cast resin retained FPD
Answer: B: Etched cast resin retained FPD 
Explanation: Etched cast resin-retained FPDs (micromechanical retention-"maryland bridge")