During the first battle of the korean war in june of 1950

On June 25, 1950, the Korean War began when some 75,000 soldiers from the North Korean People's Army poured across the 38th parallel, the boundary between the Soviet-backed Democratic People's Republic of Korea to the north and the pro-Western Republic of Korea to the south.

I really hoped this is what you were looking for

the answer your looking for is c. : )