This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Obstetrics, Subject name: Gynaecology & Obstetrics
Of the following events in labour and delivery, arrange them in their right sequence of appearance: 1. Flexion2. Internal rotation3. Restitution4. External rotation5. Delivery by extention6. Descent7. Engagement 
Select and explain. 
A. 7-6-1-2-5-3-4, B. 7-1-6-5-2-4-3, C. 7-1-5-6-5-3-4, D. 6-7-1-5-2-3-4
A: 7-6-1-2-5-3-4
Answer: A: 7-6-1-2-5-3-4 
Explanation: None