Which business structure is NOT legal for an association?

The correct answer highlights that a sole proprietorship is not a suitable legal structure for an association. This is because a sole proprietorship is owned and operated by a single individual, meaning it lacks the necessary characteristics that define an association, which is typically a group of individuals who come together for a common purpose. Associations generally involve multiple members and often require a formalized structure, including bylaws and shared governance, which a sole proprietorship does not provide.

In contrast, business structures like unincorporated associations, partnerships, and stock corporations allow for multiple participants and provide mechanisms for joint operations, shared responsibilities, and liability management, aligning more closely with the functions and needs of an association. These structures are designed for collaborative efforts and the pooling of resources among a group, making them legally recognized options for associations.