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
[{'content': 'There is spontaneous rupture of the Achilles tendon in an 18-year-old male. It is most likely to be due to excess stress beyond - \nSelect and explain. \nA. Tendon strength, B. Bone strength, C. Muscle strength, D. Musculotendinous junction strength', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A rupture of the Achilles tendon occurs when the tendon is stretched outside beyond its capacity.\nThe most common site of rupture is the "watershed" less vascular area of tendon, which is 4 cm proximal to its insertion on calcaneum.', 'role': 'assistant'}]