Final answer:
The implicit detail from the text that can be inferred is that Jenna is giving a speech, as she is addressing her classmates from a stage and is being photographed, indications of a formal speaking event.
Step-by-step explanation:
An implicit detail from the text is something that is not directly stated but can be inferred from the information provided. When you analyze the given passage, the implicit detail is that Jenna is giving a speech. This is suggested by her addressing an audience of classmates and the mention of her beginning to speak after being announced, while standing on a stage. The flashing of cameras emphasizes a formal event and her role in it, which supports the idea of her delivering a speech.