Explanation:

- Harangue: This is indeed the correct word. It refers to a long and aggressive speech, often lengthy and passionate.

- Eloquence: This refers to the practice or art of using language with fluency and aptness. It's a synonym for persuasive and effective speech, but not necessarily aggressive.

- Prologue: This is an introductory part of a discourse, poem, or novel, not a long aggressive speech. It introduces a story, setting the stage for the main events.

- Discussion: This involves talking about something to reach a decision or to exchange ideas, not specifically aggressive or long.

Your answer is: