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
Looseness seen in a recently delivered RPD is due to: 
Select and explain. 
A. Defective occlusal balancing, B. Passive clasp on abutment, C. Thin flange, D. Insufficient overlap on posterior teeth
A: Defective occlusal balancing
Answer: A: Defective occlusal balancing 
Explanation: None