This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
At the end of 5th week of gestation, how many numbers of somites can be seen? 
Select and explain. 
A. 24, B. 26, C. 38, D. 44
D: 44
Answer: D: 44 
Explanation: The first pair of somites arises in the occipital region of the embryo at approximately the 20th day of development, from here new somites appear in craniocaudal sequence at a rate of approximately three pairs per day until at the end of the fifth week 42 to 44 pairs are present Ref: Gray's 39e/p-210-220