The answer is A. a president pro tem.
The President pro tempore of the United States Senate is the second-highest-ranking official of the United States Senate, who presides over the chamber in the absence of the vice president.
The word in italics of speech is and adverb. Option C is correct.
The first characteristic of the word to be identified as an advern is the suffic -ly.
In this particular case, the adverb thoroughly is describing the verb captivated. So that, this is another factor to take into account in order to identify an adverb and differ it from and adjective. Adverbs describe verbs while adjectives describe and works as modifiers of nouns.
Thoroughly means in a thorough manner.
Can you be more specific? <span />
In order to answer we need to know what is rhetorical appeal and what are the types
rhetorical appeal : are three elements that are the tools of persuasion.
the three types as logos, pathos and ethos
so the answer is A