Final answer:
Public-interest groups are closely related to citizen groups, focusing on broad public issues rather than economic benefits, and include civil rights organizations as an example. They play a key role in civic engagement and democracy, aligning with the interests of ordinary citizens.
Step-by-step explanation:
The groups that are the most closely related to citizen groups are public-interest groups, which like citizen groups, focus on issues that affect the general public or specific segments of it, rather than focusing on solely economic benefits. These groups aim to influence policy in ways that benefit the interests of the public, or in defence of what they identify as the wider good, rather than on economic gain. For example, civil rights groups and environmental organizations often fall under this category. In contrast to the economic focus of business and labor groups, societal interest groups address societal issues based on demographics such as age, gender, race, and religious affiliation, which can also overlap with the interests of citizens.
As per the information provided, the types of interest groups are economic interest groups, single-issue interest groups, ideological interest groups, government groups, and public-interest groups. Each represents different group interests, ranging from the economic concerns of labor and business groups to the democratic ideals of ideological organizations. Citizen groups, which are similar to public-interest groups, are formed to express the collective interests and values of ordinary members of the community, making them a key component of civic engagement and participatory democracy.