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
Which of the following is true about acute rupture of tendc calcaneus   (tendo-achillis)? 
Select and explain. 
A. It occurs due to direct injury, B. Radiograph will confirm the diagnosis, C. Compression of calf muscles produces planterflexion of ankle, D. It usually occurs in middle aged persons
D: It usually occurs in middle aged persons
Answer: D: It usually occurs in middle aged persons 
Explanation: This is injury of middle aged persons usually occuring due to unaccustomed exercise. Direct injury is not the cause of tendon | rupture although most patients feel as if something has hit. X-Rays are of no value in diagnosis. Planterflexion of ankle on compression of calf occurs when the tendon is intact and its absence signifies tendon rupture. Surgical repair is preferable treatment.