Concussions Concussions Are Brain Injuries That Occur When a Person Receives

Concussions
Concussions are brain injuries that occur when a person receives a blow to the head, face, or neck. Although most people who suffer a concussion experience initial bouts of dizziness, nausea, and drowsiness, these symptoms often disappear after a few days. The long-term effects of concussions, however, are less understood and far more severe.
Recent studies suggest that people who suffer multiple concussions are at significant risk for developing chronic traumatic encephalopathy (CTE) , a degenerative brain disorder that causes a variety of dangerous mental and emotional problems to arise weeks, months, or even years after the initial injury. These psychological problems can include depression, anxiety, memory loss, inability to concentrate, and aggression. In extreme cases, people suffering from CTE have even committed suicide or homicide. The majority of people who develop these issues are athletes who participate in popular high-impact sports, especially football.
Improvements in diagnostic technology have provided substantial evidence to link severe-and often fatal-psychological disorders to the head injuries players receive while on the field. Recent autopsies performed on the brains of football players who have committed suicide have shown advanced cases of CTE in every single victim.
In response to the growing understanding of this danger, the National Football League (NFL) has revised its safety regulations. There is hope that these new regulations, coupled with advances in helmet design, will reduce the number of concussions player endure, and thus curb the number of CTE cases. Efforts by the NFL and other professional sports leagues are certainly laudable. However, new regulations at the professional level cannot protect amateur players, especially young people. Fatal cases of CTE have been reported in victims as young as 21. With appropriate equipment and form, tackling need not be dangerous. Proper tackling form-using the arms and shoulders to aim for a player's midsection rather than leading with the top of the head-should be taught at an early age. Youth, high school, and college leagues should also adopt safety rules even more stringent than the NFL's.
Question: Why does the author include the detail "fatal cases of CTE have been reported in victims as young as 21" in the passage?

A) To give an example of the psychological dangers of advanced cases of CTE.
B) To support the opinion that the NFL should have more stringent regulations.
C) To support the argument that safe ways to tackle need to be taught at an early age.
D) To support the argument that leagues involving young people should adopt stringent safety rules.