Q: In this task, you're given a context passage, followed by a question that needs to be answered. Based on the paragraph, you must write unambiguous answers to the questions and your answer must refer to a specific phrase from the paragraph. If multiple answers seem to exist, write the answer that is the most plausible.
Riley arrived at their location in perfect timing for the party. 
Question: What does Riley need to do before this?
A:
knock on the door