Out of the offered options, focus groups are the most useful to conduct market research.
A focus group is a research methodology based on data collection during group interactions. Demographically similar people are gathered and offered to discuss a specific topic. The discussion allows identifying what the participants think, how they behave, and what questions they have. For example, you can ask them what they think about the offered product, what they like/don’t like, what can be improved, etc.
Focusing groups offer a deeper insight despite being less objective than quantitative market research based on measuring data. You can learn information about your target audience you would never know otherwise. During the discussion, people talk about concerns that are not measured statistically. Thanks to the format of a dialog, you can get unexpected answers and findings. It enables you to tailor your product and marketing efforts to the needs of real people.