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
Minimum dosage of tetracycline which will show tooth discoloration is 
Select and explain. 
A. 5 mg/kg body weight, B. 20 mg/kg body weight, C. 50 mg/kg body weight, D. 80 mg/kg body weight
B: 20 mg/kg body weight
Answer: B: 20 mg/kg body weight 
Explanation: None