Final answer:
The correct indirect object pronoun to fill in the blank is 'le'.
Step-by-step explanation:
The correct indirect object pronoun to fill in the blank is le. In the sentence, the book is being given to someone, so the pronoun to use is le. Here's an example: Tu donnes le livre à ta copine ? Oui, je le donne. (Yes, I give it.)
Learn more about French pronouns