The correct answer is "school bus". "School bus" is a compound noun because it is formed by combining two separate words ("school" and "bus") to create a new word that represents a specific type of bus.
To determine if a word is a compound noun, we have to see if it is made up of two or more words functioning as a single noun. Without the provided options, I cannot identify a specific word. Please provide the options, and I will be glad to assist you in identifying the compound noun.
