Correct Answer :   South Korea
                                        
                                                                                
                                        Explanation : 
South Korea launched the world's first fully-fledged 5G mobile networks in April 2019.
 
The superfast communications heralded by fifth-generation wireless technology will ultimately underpin everything from toasters to telephones; from electric cars to power grids.
 
It will bring smartphones near-instantaneous connectivity -- 20 times faster than the existing 4G.