Identify the Incorrect Punctuation in a Sentence

In the passage below, identify the sentence that contains an error in punctuation. Consider how the punctuation contributes to the clarity and meaning of the sentence.

When she arrived at the event, which was meant to be a surprise party, she was overwhelmed with joy, and gratitude flooded through her. The guests; who had been waiting for hours, all shouted surprise as she entered. Despite the rain, everyone had decorated the venue beautifully and prepared her favorite meal, making it truly a memorable occasion.