Final answer:
The underlined word 'snacks' in the sentence is a noun, as it refers to food, making it a thing or object.
Step-by-step explanation:
The sentence provided is 'We barely finished our snacks before the teacher returned.' The underlined word in the sentence is 'snacks,' and based on the options given, the correct answer to identify the part of speech of the underlined word is Option 1: A. noun. 'Snacks' refers to small amounts of food eaten between meals, which makes it a thing or an object, fitting the definition of a noun. Nouns are the names of persons, places, things, or ideas. When analyzing parts of speech, it's important to look at how the word functions in the sentence to determine its correct part of speech.