Answer
Text can read supported selected links and attachments. Image and Video can use text or supported still images; Audio can use selected text. When only written text is needed, it may be used even if the source message also contains attachments or narration.
An ambiguous, unavailable or unsupported reference does not add an inferred source. A fully specified request does not need an earlier source simply because the topics match. Explicit replies, attachments, prompt links and mentions take precedence.
A selected source can provide richer details, such as a quiz’s authored questions and answers, a flashcard deck’s cards or a complete supported file. This still does not make every kind of media readable. Reply directly or attach the exact source when it matters.