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: Unknown
A lady presents with swelling of hands with shiny skin. She has a history of fracture radius and kept on POP cast for 4 weeks after which she develops this. Give the most likely diagnosis - 
Select and explain. 
A. Myositis ossification, B. Rupture of external pollicis longus tendon, C. Reflex sympathetic dystrophy, D. Malunion
C: Reflex sympathetic dystrophy
Answer: C: Reflex sympathetic dystrophy 
Explanation: Ans-C