28. According to the passage, a mass gathering _________ .
(A) causing a stampede can only be prevented by GPS, with no other effective methods
(B) resulting in a large crowd’s rush can be avoided by wristbands which monitor crowds in delayed real time for slow responses
(C) in a music festival unites everyone in happiness and joy but has deadly criminal activities when individuals participate in suspicious behaviors
(D) leading to stampedes can be prevented by using IoT technology with vibration sensors to detect unusual vibrations and alert authorities to take action