Which of the following organizations hosts the website with links to U.S. foundations?

The Foundation Center is the organization that specifically focuses on providing information about U.S. foundations and their activities. It hosts a comprehensive website that offers various resources, including links to thousands of grantmaking foundations, detailed profiles, and data on funders. This is essential for grant seekers who are looking to identify potential funding sources for their projects.

In contrast, other options serve different purposes: Charity Navigator evaluates the financial health and accountability of charities, which does not directly relate to connecting grant seekers with foundations. The National Endowment for the Arts is a federal agency that provides funding for arts organizations but does not serve as a comprehensive database for all foundations. The Grant Writers Association is a professional organization that may offer resources and support to grant writers, but it does not host a dedicated site linking to U.S. foundations like the Foundation Center does. Thus, the Foundation Center stands out as the primary source for foundation-related information.