Final answer:
Primary stakeholders are essential to a firm's survival and are directly involved with its operations, unlike secondary or tertiary stakeholders who have less direct connections.
Step-by-step explanation:
The group of stakeholders that is defined as being necessary for a firm's survival is known as primary stakeholders. These stakeholders are essential to the operations and existence of a company. The options provided indicate different levels or types of stakeholders. In this context, primary stakeholders are directly involved and impacted by the firm's activities. Conversely, secondary stakeholders, like secondary groups in society, have a less direct connection to the individual or firm. Secondary stakeholders may influence or be involved with the company, but they are not essential to its survival, serving more task-based or practical roles. Similarly, tertiary stakeholders have an even less direct connection and influence. Special interest groups are a type of stakeholder or interest group, but they are not defined by their necessity to a firm's survival.