Final answer:
The dominant response in social facilitation means that in the presence of others, performance improves on well-practiced tasks due to increased arousal.
Step-by-step explanation:
The notion of the dominant response, as explained in social facilitation, suggests that when the presence of other people arouses an individual, their performance on a task can be influenced. Specifically, the correct answer to the student's question is: b) Your performance improves on well-practiced tasks. This occurs because when a task is well-learned or simple, the arousal caused by the presence of others tends to enhance one's performance. This is contrasted with a situation in which the task is complex or novel, where performance can suffer under the same conditions of arousal due to the presence of others.