Skill-related factors primarily refer to abilities that are essential for performing specific movements or sports. Among the given choices, the correct response is Both A and C (agility and reaction time, cardiovascular efficiency).
However, if we have to strictly classify skill-related factors, agility and reaction time are the most directly related to skill performance, whereas cardiovascular efficiency is often considered a health-related component rather than a skill-related one.
So the best response considering skill-related factors alone would emphasize agility and reaction time.