Final answer:
Structuring the passage as dialogue followed by private thoughts allows us to see how Winston interprets his interaction with another Party member.
Step-by-step explanation:
The effect of structuring the passage as dialogue followed by private thoughts is that it shows how Winston interprets his interaction with another Party member (option b). By presenting the dialogue first, the reader gains insight into Winston's thoughts and feelings about the conversation. This helps to deepen our understanding of his character and his perception of the events unfolding in the novel.