What type of information must be preserved and distributed along with digital video signals?

The correct choice is Active Format Descriptor (AFD) and Program and System Information Protocol (PSIP) because these elements provide essential information that helps in the proper display and playback of digital video signals.

AFD is a standardized method for indicating the format of the video content and how it should be displayed, particularly in cases where the aspect ratio needs to be adjusted or the video content is being shown on various screens. It ensures that viewers receive the intended visual presentation without distortion or inappropriate cropping.

PSIP is used to communicate information about digital broadcast content. It includes crucial data about the programming, such as scheduling and channel information, which enhances the user experience by allowing for better navigation and selection of broadcast channels.

While metadata broadly encompasses various types of information associated with digital files, including descriptive details and technical attributes, the specific importance of AFD and PSIP lies in their tailored role in managing how video content is rendered and delivered to the end user.