Answer:
The answer is A) The speaker talks to her sister who understands politics. I took the test.THIS ANSWER IS CORRECT.
Them would be the correct pronoun for this sentence because books is plural and is an object, so its pronoun must be third person. The 3rd person plural pronoun in English is they, and its objective/accusative form (the form used when the item is the object of a verb) is them, so there's your answer.
I'm no expert on linguistics, but I think the first statement speaks out the most to me
