This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: New born infants, Subject name: Pediatrics
Upper segment to lower segment ratio at bih is ___________ 
Select and explain. 
A. 1, B. 1.3, C. 1.5, D. 1.7
D: 1.7
Answer: D: 1.7 
Explanation: The U/L ratio (upper body segment :lower body segment) at bih is about 1.7; at age 3 years it is 1.3; at greater than 7 years, it is 1.0 with the upper body segment and lower body segment being about equal. Of note, higher U/L ratios are noted in sho-limb dwarfism and other bone disorders such as rickets. Reference: GHAI Essential pediatrics, 8th edition