Final answer:
Once you have chosen a sound to focus on in the listening process, the next step is to assign meaning, which involves understanding the message conveyed by the sound. Option number a is correct.
Step-by-step explanation:
In the context of the five steps of the listening process, once you have chosen a sound to focus on, the next step you must do is assign meaning. This involves understanding the message that is being conveyed by the sound. Therefore, the answer to the question is (a) Assign meaning.
After choosing a sound to focus on (which involves making an effort to attend to that particular sound), assigning meaning is essential for comprehension. It enables you to interpret and understand the content and the emotional tone of the message. This step is followed by remembering, evaluating, and finally providing feedback, which closes the listening cycle.