The correct answer is d. the speaker's appearance. The factors that can affect a person's impression of the arguments in a radio speech include not only the speaker's reasoning but also the speaker's appearance. While radio is an audio medium and does not involve visual cues, the speaker's appearance can still influence the listener's perception of the arguments being made. This can include factors such as the speaker's voice, tone, and overall presentation style, which can indirectly contribute to their impression of the arguments. However, it's important to note that the specific impact of appearance may vary depending on the individual listener's preferences and biases.
