Place phobia mainly manifests as a fear of certain specific environments, such as high places, squares, objective environments, and crowded public places. It often starts with a spontaneous panic attack, and then produces expected anxiety and avoidance behaviors, which in turn leads to conditionalized Some clinical studies have shown that patients with place-phobia are often accompanied by panic attacks. However, some experts believe that the first panic attack is a necessary condition for the onset of place-phobia, so they believe that place-phobia is a consequence of the development of panic attacks. Under the category of panic disorder. Which of the following, if true, would most question the above-mentioned expert opinion? ['The course of place phobia often fluctuates, and many patients may improve or even ease in the short term.', 'Place phobia may be genetically related and linked to panic disorder.', 'Research finds that onset phobia is more than 40 years old, and its course tends to be chronic.', 'Research Finds that Fear of Place Occurred in About Patients Prior to Panic Attack.']