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
A child has the permanent molar and 3 deciduous molars filled with amalgam. 2 other deciduous teeth were cariously decayed, 2 deciduous upper incisors are missing. The decayed and filled score of child is: 
Select and explain. 
A. 3, B. 5, C. 7, D. 8
B: 5
Answer: B: 5 
Explanation: None