This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Substance abuse, Subject name: Anatomy
Which of the following is a symptom of opioid withdrawal 
Select and explain. 
A. vomiting, B. delirium, C. constipation, D. meiosis
A: vomiting
Answer: A: vomiting 
Explanation: In opioid withdrawal ALL ORIFICES BLEED Lacrimation, vomiting, rhinorrhea, diarrhea, mydriasis, kicking the habit, muscle cramps, abdominal cramps, tachycardia, cold turkey Ref. kaplon and sadock, synopsis of psychiatry, 11 th edition, 660