PM2.5 refers to tiny particles with a diameter of fewer than 2.5 microns (less than 1/20 of the hair strand) in the atmosphere. Their size allows them to penetrate into the lungs of the human body, causing serious harm to human respiratory health. In recent years, China In the central and eastern regions, large-scale and long-term haze weather has occurred, and the PM2.5 index has risen in many places. In response, a city has introduced measures such as vehicle single and double number restrictions to deal with air pollution. In favor of such a vehicle restriction measure, it is believed that this approach has little impact on the decline of the city's PM2.5 index and cannot fundamentally change the state of air pollution in the city. Which of the following, if true, would best support the opinion of the above experts? ['Vehicle exhaust is one of the important causes of air pollution in this city.', 'Relative to industrial pollution, the impact of vehicle exhaust on air pollution is small.', 'The rise of the PM2.5 index in this city is mainly caused by the impact of air pollution in other regions.', 'Citizens in the city strongly urge the government to strengthen the management of smog weather.']