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: Forensic Medicine
Most common cause of second trimester aboion: CMC (Vellore) 14 
Select and explain. 
A. Chromosomal defect, B. Cervical incompetence, C. Abnormality of uterus, D. Infections
B: Cervical incompetence
Answer: B: Cervical incompetence 
Explanation: Ans. Cervical incompetence