What is the function of the pronoun "their" in the sentence?

As the eagle chased the rabbits, the mice also got scared, and ran into their holes.
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to replace the antecedent "mice" in the sentence
to emphasize that the noun "mice" should be singular
to help describe the action that the noun "mice" is making
to describe the antecedent "mice" in the sentence

The function of the pronoun "their" in the sentence is to replace the antecedent "mice" in the sentence.