Sara is constantly worried that she is going to die in a car accident. When she was a child, her father died in a car accident on his way to pick her up from school. However, her fear of dying in a car accident didn't occur until she went away to university at the age of 18. Sara reports that she often has intrusive thoughts of being involved in a motor vehicle accident and that these thoughts persist no matter how much she tries to ignore them. Sara avoids driving or being in a car whenever possible. If she has to ride in a car, Sara spends more than an hour checking it over before she gets in. Sara understands that these thoughts and her avoidance are negatively affecting her life. Based on this information, which anxiety disorder do you think Sara most likely has?