A focus group is an example of:

A focus group is indeed categorized as a guided discussion for qualitative data collection. This method involves collecting rich, detailed insights from a small group of participants, typically facilitated by a moderator who leads the discussion on specific topics. The goal is to explore participants' thoughts, feelings, and opinions in a dynamic setting where they can interact with one another.

This format is designed to garner diverse perspectives and stimulate conversation, which often reveals deeper insights than individual interviews or surveys might. Focus groups are particularly valuable in sociology for understanding social phenomena, cultural norms, and group dynamics, highlighting the qualitative nature of the findings they produce. In contrast, the other options do not align with the properties and purpose of focus groups; for instance, quantitative research methods focus on numerical data and statistical analysis, structured interviews follow a strict question format for uniformity, and individual surveys gather data from one person at a time rather than a group interaction.