Final answer:
a. A lobbying organization representing a nonprofit organization will probably have the most difficult time raising money, as they often depend on limited donations and do not have the monetary power of for-profit entities.
Step-by-step explanation:
Out of the types of interest groups mentioned, a lobbying organization representing a nonprofit organization will likely have the most difficult time raising money. Nonprofits often rely on donations and grants and generally do not have the financial resources that for-profit entities possess. Conversely, a lobbying organization representing a for-profit organization such as Verizon or Coca-Cola, will typically have more financial means to influence policy due to the capacity to generate significant revenue and allocate funds for lobbying efforts.
A membership organization relying on appeals to purpose can sometimes struggle to raise funds, as they depend on aligning with the specific interests or values of potential members. Such organizations often focus on a broader public interest rather than particularized benefits, which might not be as compelling for people to contribute financially.
Lastly, a membership organization relying on solidary incentives might face challenges in fundraising, but these groups offer social benefits to members that can drive membership dues as a source of revenue. These incentives can help overcome the collective action problem by providing a personal benefit (such as community or recognition) in exchange for contributions.