Hello. You did not show the excerpt to which the question refers, which makes it impossible for that question to be answered accurately.
However, we can affirm that the sentence that you must select is one that shows statistical and / or scientific information, which allows the proof of a certain position or argument in relation to the text's theme. In that case, you should look for that type of information in the text you have.
it will be the socondary source
Marriage difficulties adversely affect parent-child communication.