The correct answer is D. He uses pathos to appeal to the listeners' suspicion and fear of Germany.
Step-by-step explanation
When a speaker uses Pathos in a speech he makes use of the emotions and empathy that causes his speech and charisma in the audience. Usually, these speeches are used by politicians or candidates to move large groups of people. In the fragment of the speech, Churchill refers to the characteristics of his enemy (German) as "there is no dirty trick he will not do" to arouse fear in the audience. Therefore, the correct answer is D. He uses pathos to appeal to the listeners' suspicion and fear of Germany.