Final answer:
All options given (festivals, sports events, charity fundraisers, and business events) accurately represent common categories used when classifying events by form or content.
Step-by-step explanation:
When classifying events by form or content, all the following categories can be used: festivals, sports events, charity fundraisers, and business events. In this context, each category represents a common type of event that is organized with specific goals and target audiences in mind. Festivals typically involve cultural, artistic, or community celebrations. Sports events focus on athletic competitions. Charity fundraisers are events with the goal of raising money for a cause or organization. Business events are professional gatherings such as conferences, meetings, or trade shows.