This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Radiology Q Bank, Subject name: Radiology
16 yr old, obese female presented with history of bilateral hip pain from a long duration. Endocrinology tests show hypothyroidism. She has a painful limping gait. Which of the following investigation is of no use in diagnosis of this condition? 
Select and explain. 
A. X-Ray, B. MRI, C. CT, D. USG
D: USG
Answer: D: USG 
Explanation: History given is suggestive of SCFE( Slipped capital femoral epiphysis). X-Ray showsa Trethowan's sign CT is used for Acute/Chronic slip MRI is IOC. USG has no role in diagnosing this condition.