For years, a considerable number of students on West County High School's track team complained about shin splints (medial tibial syndrome). However, during the most recent season, the number of students who complained about shin splints dropped significantly. School officials assert that this reduction in complaints occurred entirely as a result of the school's decision to build a new running track that provided a softer running surface, which absorbed much of the shock on the knees and shins that occurs when running and causes shin splints.
Which of the following, if true, most severely weakens the school officials' explanation for the decrease in complaints about shin splints?
A) As a result of West County High School's adoption of better medical staff and new medical scanning devices, many students whose complaints would have been diagnosed in years past as an instance of shin splints are now diagnosed with a different condition.
B) West County High School built its track after a number of neighboring schools with similar track teams built new tracks and each school saw the number of complaints about shin splints drop.
C) This past season, members of West County High School's track team received and wore new and highly acclaimed shoes designed to soften the impact of running on the shin and knee.
D) This past season, the total number of students who complained of pain while running rose.
E) The maker of the new track claims that on average, complaints about shin splints fall 25% when its tracks are implemented.

[spoiler]OA C
Though i answered the question correctly, but i think A also has competence in weakening the answer choice[/spoiler]