What is the primary footage for non-narrative or interview-based film called?

The primary footage for non-narrative or interview-based film is appropriately referred to as A-roll. This footage typically contains the main content, which may include interviews or other primary visual narrative elements. In interview-based films, A-roll showcases the subject being interviewed, capturing their responses and emotions, thereby forming the backbone of the film's storytelling.

On the other hand, B-roll is supplementary footage that may include cutaway shots, contextual visuals, or other scenes that enhance the narrative or provide additional context to the A-roll. While both types of footage are essential in the filmmaking process, A-roll specifically refers to the main shots that hold the primary storyline or interview content, making it the correct choice in this context.