A focus group is a technique that involves gathering a group of people who share some characteristics or interests related to a product, service, or issue, and asking them for their opinions, perceptions, or feedback. The project manager acts as a moderator or facilitator who guides the discussion and records the results. A focus group can help to collect information from a representative sample of the target population, explore ideas, identify needs and preferences, and support the completion of larger projects. The other options are not correct because:
A demonstration is a technique that involves showing the features or capabilities of a product, service, or process to the stakeholders or customers, usually in a live or simulated environment. A demonstration can help to validate the requirements, obtain feedback, and verify the functionality of a deliverable.
A workshop is a technique that involves bringing together a group of stakeholders or experts to work on a specific topic, problem, or issue, usually in a structured and facilitated way. A workshop can help to define the scope, plan the activities, identify the risks, resolve the conflicts, and generate the solutions of a project.
Brainstorming is a technique that involves generating a large number of ideas or alternatives for a problem or opportunity, usually in a creative and spontaneous way. Brainstorming can help to enhance the creativity, diversity, and quality of the ideas, and encourage the participation and collaboration of the team members. Reference = CompTIA Project+ Study Guide: Exam PK0-005, 3rd Edition, Chapter 6: Planning Projects, Part 2 (Scope, Quality, and Risk), page 191; CompTIA Project+ Certification Exam Objectives, Domain 2: Project Planning, Objective 2.1: Given a scenario, create a project charter and project management plan.