A 9-year-old client who has been diagnosed with autism spectrum disorder would be expected to display which behavior?

The correct answer is C because children with autism spectrum disorder often exhibit social difficulties, including spending time alone and showing little interest in making friends. This behavior aligns with the characteristic of social impairment commonly seen in individuals with autism. Choice A is incorrect because motor and vocal tics are more commonly associated with conditions like Tourette syndrome, not autism. Choice B is incorrect as becoming overly attached is not a typical behavior associated with autism. Choice D is incorrect as trichotillomania, the urge to pull out one's hair, is not a core symptom of autism. Overall, the key point is that social difficulties and lack of interest in forming friendships are hallmark behaviors in individuals with autism spectrum disorder.