What are the two options for generating thumbnails of video files in FTK?

The correct answer identifies one of the primary methods for generating thumbnails of video files in FTK, which is based on selecting fixed intervals of the video's total length for thumbnail creation. Specifically, the percentage method allows the examiner to specify a percentage of the video's playtime, ensuring that thumbnails represent the content at different stages throughout the video. This approach can effectively provide a broad visual overview of the video’s content by capturing key moments at specified intervals, enhancing the forensic analysis process.

The other options, while relevant to different aspects of video processing or file analysis, do not pertain specifically to the mechanism of thumbnail generation within FTK. For instance, generating thumbnails based on intervals in time (such as every "n" seconds) is another distinct approach to capture video frames; however, it is not covered by the answer provided. Audio format tracking and resolution adaptation focus on different facets of media analysis and do not directly relate to thumbnail generation methods. Understanding these concepts is essential for a comprehensive grasp of the capabilities of FTK in digital forensic investigations.