Define the term "social influence".

The correct choice accurately captures the essence of social influence, which refers to the processes through which individuals' thoughts, feelings, and behaviors are affected by the presence or actions of others. This concept encompasses a variety of interactions, including conformity, compliance, and obedience. It highlights how social context can shape individual psychology and lead to changes in attitudes or behaviors.

The other options either focus on specific contexts or mechanisms that are subsets of social influence but do not encompass the full definition. For instance, changes in personal health due to societal norms relates more to health psychology and does not fully address the broader aspects of individual change in thoughts or behaviors. The influence of media on public opinion is a specific manifestation of social influence, focusing narrowly on communication and perception. Similarly, the impact of advertising on consumer behavior describes a particular scenario of social influence in a commercial context but does not reflect the overall definition of how individuals interact with and are affected by others in various social settings.