The passage concludes that parents have little reason to trust their own ratings of the educational value of children's TV shows.
Why? Because a study found that parents' ratings were influenced by how much they personally enjoyed the shows and rarely accounted for the views of educational psychologists on the programs' educational value.
Answer choice (C) is incorrect because the passage does not address parents trying to decide whether a child should watch the show. The passage is simply arguing that parents shouldn't trust their own ratings of the educational value of said shows because of the underlying influences on these ratings.
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