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
Closure of coronal sutures starts at age of - 
Select and explain. 
A. 20 years, B. 25 years, C. 30-35 years, D. 50-60 years
B: 25 years
Answer: B: 25 years 
Explanation: This question is tricky one. Most of the guides have given option c is the answer. Which is incorrect.
Coronal suture is completely obliterated at 35-40 years. But, read the question carefully, examiner is asking when the closure starts (not completes).
Closure of coronal, lambdoid and sagittal sutures starts at inner side at 25 years. And it is complete on outer side :-
Sagittal suture → 30-35 years.
Coronal suture → 35-40 years.
Lambdoid suture →  45-50 years.