Final answer:
All the options listed - agility, balance, and speed - are skill-related fitness components, which are crucial for performance in various sports and activities.
Step-by-step explanation:
The question is related to skill-related fitness components. These components refer to physical abilities that contribute to performance in sports and activities requiring motor skills. The components listed in the options, agility, balance, and speed, are all aspects of fitness that directly contribute to one's ability to perform specific physical tasks effectively. These components are related to the ability to perform specific physical tasks efficiently and effectively. Agility is the ability to change direction quickly, balance is the ability to maintain a stable position, and speed is the ability to move quickly.
Therefore, the correct answer to the question 'Which of the following is a skill-related fitness component?' is d. All of the above are skill-related fitness components.