Final answer:
Young athletes can begin to understand empathy and help others during preadolescence with a coach's guidance, as it is a time of significant cognitive and psychosocial development when influenced by teamwork and positive role models.
Step-by-step explanation:
The question revolves around when young athletes are capable of understanding empathy and helping others with a coach's guidance. During preadolescence, generally between the ages of 11 and 12 years, children start to develop the ability to think abstractly and begin to form a sense of identity. They are starting to experience significant cognitive and psychosocial development which can be shaped by external influences such as coaching and teamwork. Empathy and cooperation are important aspects of social development and can be introduced during this stage.
In the context of young athletes, coaches play an important role in guiding them to understand empathy. Through sports, athletes can learn the value of teamwork, respect for peers, and the importance of contributing to a community, setting a foundation that extends beyond the field. Thus, the correct option is (a) preadolescence.