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: Pharmacology
Which drug can be safely used in lactating mothers? 
Select and explain. 
A. Ampicillin, B. Chloramphenicol, C. Ciprofloxacin, D. Erythromycin
D: Erythromycin
Answer: D: Erythromycin 
Explanation: None