Final answer:
The most likely finding in a child with separation anxiety disorder is that the child's mother has an anxiety disorder.
Step-by-step explanation:
Which finding would be most likely in a child diagnosed with separation anxiety disorder? Among the provided options, the most likely finding would be that the child's mother is diagnosed with an anxiety disorder. This choice aligns with the research that suggests anxiety disorders can have a genetic component or that children can be influenced by their parents’ anxieties through both environmental factors and modeling behaviors. A child's exposure to a caregiver with an anxiety disorder may increase the likelihood of the child developing similar patterns of anxiety, such as separation anxiety disorder.
In contrast, while a history of antisocial behaviors, an extroverted temperament, or inconsistent parenting styles might affect a child's development, they are not as directly linked to the development of separation anxiety disorder as is the possibility of inherited or learned anxious behaviors from a caregiver with an anxiety disorder.