Answer: B) Compound noun.
Explanation: a noun is a word or a group of words (other than a pronoun) used to identify or to name any of a class of people, places, or things. A compound noun is a noun made up of two or more existing words. In the given sentence we can see an example of a compound noun in the word "great-grandfather" which as we can see, is formed by the two words "great" and "grandfather."
