Answer : 4. "Japan"
Explanation :

A Japanese consortium unveiled the world's first high-speed 6G prototype gadget, surpassing 5G by 20 times. Developed by DoCoMo, NTT, NEC and Fujitsu, it can transmit data at speeds of up to 100 Gbps, which has been successfully tested indoors and outdoors. However, 6G is still in the development stage and is not ready for commercial use. Despite its impressive speeds, network technology has inherent shortcomings.