Final answer:
John is at the 'receiving' stage of the listening process, where he acknowledges Sarah as the speaker and pays attention to her, setting the stage for the subsequent phases of effective communication.
Step-by-step explanation:
In the scenario described, John is at the receiving stage of the listening process. This stage involves the listener noticing that someone is speaking and giving their attention to the speaker. In contrast, the responding stage would be about providing feedback after listening, the understanding stage would focus on comprehending the message, and the evaluating stage involves judging or critically thinking about the information presented. Since John is initially shifting his focus to Sarah to acknowledge that she has started speaking, he is in the receiving phase, which is the foundation for effective communication and an essential step before responding, understanding, or evaluating can occur.