Cottrell proposed that the cyclist may perform better when they are racing against each other rather than when they are alone. This is because of:

Evaluation apprehension

The correct answer is Co-action and evaluation apprehension.

Cottrell's social facilitation theory suggests that the presence of others can either enhance or hinder performance, depending on the nature of the task and the individual's level of skill. In the case of cyclists racing against each other, coaction can facilitate performance because the presence of competitors can increase arousal levels and motivation. Additionally, evaluation apprehension, or the fear of being negatively evaluated by others, can also play a role in motivating cyclists to perform better.

While evaluation apprehension can also lead to poorer performance, in the context of competitive cycling, the presence of clear goals and the desire to avoid negative evaluation can motivate cyclists to push themselves further than they might in a solo setting.