Final answer:
The rhetorical device in Patrick Henry's speech exemplifies the unsuccessful peaceful efforts made by the colonists, implying the need for stronger measures through the use of parallelism.
Step-by-step explanation:
The rhetorical device used in the excerpt from Patrick Henry's 1775 speech serves to emphasize the colonists' exhaustive attempts at peaceful solutions with Great Britain and to highlight the ineffectiveness of those attempts, thus justifying stronger action. The correct answer is A, as the use of parallelism underscores the various peaceful methods, such as argument and supplication, the colonists employed over the past decade, which had all been unsuccessful. The repetition of the processes they have gone through without any new results or terms to offer brings attention to the futility of their actions and suggests that radical change is necessary.