You are answering a USMLE-style medical question. Question: A 39-year-old African-American woman presents to the emergency room with hip pain. She has a past medical history significant for sarcoidosis which was recently diagnosed 6 months ago and is currently being treated. She reports that the pain started 2 weeks ago and is localized to the left hip and groin. The pain has been getting progressively more intense. Her temperature is 98.1°F (36.7°C), blood pressure is 122/78 mm Hg, pulse is 80/min, respirations are 13/min, and oxygen saturation is 98% on room air. Physical exam is notable for pain with manipulation without restriction of range of motion of the hip. Which of the following is the most sensitive test for this condition? Options: A) MRI of the hip B) Radiograph of the hip C) Radionuclide scan of the hip D) Ultrasound of the hip Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.