Final answer:
The participial phrase 'sitting in the guidance office' in the sentence modifies the word 'Carlee'. She is the one performing the action of sitting in the guidance office.
Step-by-step explanation:
In the given sentence, 'While sitting in the guidance office, Carlee completed her resume for the job opening', the underlined participial phrase is modifying the word 'Carlee'. Participial phrases always modify the subject of the sentence, and in this case, 'Carlee' is the subject who is 'sitting in the guidance office'. So, the correct answer is C) Carlee.
Learn more about Participial Phrases