Which situation exemplifies social facilitation?

The scenario where a runner performs better during a race with an audience exemplifies social facilitation because it highlights the impact of the presence of others on an individual's performance. Social facilitation theory suggests that individuals often perform better on tasks when they are in the presence of an audience or even when they know they are being observed. This is particularly true for tasks that are well-learned or practiced, as the audience can provide motivational support, enhance focus, and increase arousal levels.

The athlete's enhanced performance due to the audience's presence illustrates this principle effectively. The competitive environment and encouragement from spectators can lead to higher levels of adrenaline, resulting in improved physical performance. Other situations listed do not demonstrate this effect, as they involve individuals performing tasks in solitude, where the influence of others is absent.