Which of the following is NOT an example of a transition word?

Transition words serve to connect ideas, sentences, or paragraphs in a piece of writing, guiding the reader through the text and indicating relationships between concepts. Words such as "however," "moreover," and "furthermore" are all transition words that help to show contrast, addition, or organization within a narrative or argument. They are essential in making writing coherent and smooth.

On the other hand, "quickly" is an adverb that describes the manner in which an action is performed, rather than serving a connective function in discourse. Its role is to modify a verb, giving information about the speed of the action, rather than linking different ideas or statements. This makes "quickly" distinct from the other choices, which function specifically to transition between thoughts or points in writing.