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
Drug which acts on motilin receptors? 
Select and explain. 
A. Erythromycin, B. Tetracycline, C. Norfloxacin, D. Chloramphenicol
A: Erythromycin
Answer: A: Erythromycin 
Explanation: None