Which type of group is developed spontaneously based on shared interests?

The correct choice is the informal group as it is formed naturally among individuals who share common interests or social connections. These groups arise spontaneously without formal organization or structure and are often characterized by closer personal relationships and emotional bonds. Informal groups can enhance communication, foster collaboration, and improve morale within an organization, as members feel a sense of community and mutual support.

In contrast, formal groups are deliberately created for specific organizational purposes, usually with a defined structure and objectives. Functional groups are established based on the functional roles of employees within the organization, such as departments like marketing or finance, while task groups are formed for a specific project or task, often disbanding once their goal is achieved. Thus, the spontaneous and personal nature of informal groups makes this answer the most accurate choice.