Final answer:
The best word to complete the sentence is 'oratory,' which refers to the skill of persuasive public speaking and is closely tied to the context of the sentence. Option a is the correct answer.
Step-by-step explanation:
The word that best completes the sentence 'The crowd was swayed by Anthony's stirring _____.' among the provided options is oratory. This term is closely associated with the art of speaking in public, which is designed to persuade or sway an audience.
The context of the sentence suggests that Anthony is impacting the crowd through his speech, which is more specific than a mere performance or presentation. Additionally, the word rhetoric could be applicable, but it generally refers to the art of effective or persuasive speaking or writing, especially the use of figures of speech and other compositional techniques.
'Oratory' is the best fit because it specifically denotes the skill of persuasive public speaking. The ancient Greeks and Romans valued oratory highly and considered it a key part of political life, as exemplified by famous orators like Cicero.