Concept:Pressure groups are organizations that influence government policies by representing and expressing the shared interests of their members.
Explanation:Pressure groups do not nominate presidents or prepare budgets; those are duties of political parties and the executive.
Their main role is to articulate, or clearly express, the opinions and concerns of their members to decision-makers.
This helps the government understand public needs, especially for minority or special-interest groups.
Therefore, the function that matches their purpose is voicing members' opinions.
Answer:C. Articulate the opinion of their members.