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
Minocycline is not used in the 3 mix antibiotic paste because of only one adverse effect 
Select and explain. 
A. Discolouration of crown, B. Roots become brittle, C. It reaches out readily, D. It has least antimicrobial effect
A: Discolouration of crown
Answer: A: Discolouration of crown 
Explanation: None