C). Concussion experts will help athletes only at organized games.
Explanation:
In the given passage, the author substantiates all the given claims except for the claim regarding 'assistance of concussion experts being available to the athletes only at organized games.' <u>There is no clear description regarding this claim that could verify or prove the reliability and convince the audience to believe in it</u>. The other claims are supported with sufficient details that help establish the validity of the assertion and make them credible. Therefore, <u>option C</u> is the correct answer.
