What is the purpose of a trailer?

The purpose of a trailer is to showcase highlights of a film to attract audiences. Trailers are specifically designed to generate interest and excitement about a movie by presenting key elements such as compelling scenes, dramatic moments, intriguing dialogue, and captivating visuals. This concise preview aims to entice viewers to see the full film, often by highlighting action, emotion, or unique aspects of the storyline without giving away the entire plot.

While other options mention aspects of filmmaking, they do not align with the primary goal of a trailer. A detailed overview of the film's script would be too lengthy and would spoil the experience for potential viewers. Demonstrating behind-the-scenes footage focuses more on the filmmaking process rather than the narrative and excitement of the story itself, which is what attracts audiences. Lastly, explaining production techniques is more suited for educational content rather than serving as a marketing tool to draw in an audience for the film. Thus, the function of a trailer is effectively summarized in its role to highlight and promote the film.