Final answer:
The rhetorical technique in Churchill's speech excerpt is parallelism, contrasting Allies' setbacks with German triumphs to highlight higher Allied morale. The correct answer is option D.
Step-by-step explanation:
The rhetorical technique used in the excerpt from Prime Minister Winston Churchill's "Their Finest Hour" speech is parallelism. Churchill contrasts the series of defeats and disappointments experienced by the Allies with the aggressive triumphs of the Germans. Despite the apparent setbacks, Churchill notes that the morale of the Allies was ultimately higher than that of their adversaries, illustrating the parallel structure in the misfortunes and resilience of the Allies versus the victories and invading positions of the Germans.