Final answer:
The correct form to complete the sentence is 'están'.
Step-by-step explanation:
The correct form to complete the sentence with is están.
The sentence 'Esos libros están míos.' translates to 'Those books are mine.'
In this case, we use the verb 'estar' because we are referring to the temporary condition of possession. 'Ser' is used to talk about permanent qualities or attributes.
Learn more about Using the correct form of ser or estar