Final answer:
In this sentence, "mine" is a pronoun.
Step-by-step explanation:
In the sentence, "mine" is a pronoun. Pronouns are words that are used in place of nouns to avoid repetition.
For example, in the sentence, "This book is mine", the word "mine" is used in place of a noun, such as "my book", to avoid the repetitive use of the noun.
Therefore, in the given sentence, "mine" is a pronoun.
Learn more about parts of speech