Cathy, Who Has Not Played Organized Sports Before, Has Joined

Cathy, who has not played organized sports before, has joined the middle school track team. A few weeks after she started, she experienced severe pain in her legs, especially around the knees. What might explain this sudden pain and inflammation around her knees?

A) Normal growth of the muscles and tendons in response to an increase in physical activity.
B) Abnormal growth of the bones in her knee and lower leg that is often seen at this age.
C) A condition known as Osgood-Schlatter disease.
D) A degenerative condition known as the Kenyan Threshold.
E) Abnormal growth in ligaments and tendons, often referred to as Potocki-Shaffer's syndrome.