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
Tetracycline should be avoided from: 
Select and explain. 
A. 4 months to 8 years after birth, B. 4 months in utero to 8 years after birth, C. 4 weeks in utero to 8 years after birth, D. 12 weeks in utero to 8 years after birth
B: 4 months in utero to 8 years after birth
Answer: B: 4 months in utero to 8 years after birth 
Explanation: Tetracycline when given from mid-pregnancy to 5 months of extrauterine life, the deciduous teeth are affected with discoloration. When given between 3 months to 6 years of age, they affect the crowns of permanent anterior dentition. They should be avoided from 4 months in utero to 8 years.