Which among the following country tests the World's fastest bullet train, recently?

Japan is testing the fastest-ever shinkansen bullet train, capable of speeds of as much as 400 kilometers (249 miles) per hour. Called the Alfa-X, the train is scheduled to go into service in 2030. Rail company JR East plans to operate it at 360 kilometers per hour. That would make it 10 kph faster than China's Fuxing Hao, which links Beijing and Shanghai and has the same top speed.