Theft cases in a residential community are frequent. At the request of the residents, the property installed a multifunctional anti-theft system for the community at the beginning of last year. As a result, the incidence of theft in this community has dropped significantly. Reduce the incidence of theft. Which of the following, if true, would best strengthen the above conclusion. ['Last year, the number of thefts in residential communities without such a theft system increased significantly.', 'Another anti-theft system is also installed in another nearby residential area, but the effect is not good.', 'Since the beginning of last year, the city has strengthened law and order management, and the number of theft cases has decreased significantly.', 'The property adopts other anti-theft measures, which also plays a role in preventing theft cases.']