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: Orthopaedics
A 50 year oldlady sprained her ankle 2 months back from which she made a steady recovery. 2 months after the injury she gradually developed severe pain in her right ankle with significant limitation of ankle movement. Clinical examination reveals edema and shiny skin. What is the likely diagnosis ? 
Select and explain. 
A. Fibromyalgia, B. Complex Regional pain syndrome Type I (CRPS I), C. Complex Regional pain syndrome Type II (CRPSII), D. Peripheral Neuropathy
B: Complex Regional pain syndrome Type I (CRPS I)
Answer: B: Complex Regional pain syndrome Type I (CRPS I) 
Explanation: Presence of severe persistent pain, edema, decreased range of motion (motor features) and trophic changes (shiny skin) two month after sustaining a soft tissue injury suggests a diagnosis of Complex Regional Pain Syndrome Type I (Reflex Sympathetic Dystrophy).