Please help ive been stuck on this question for so long

Why was mao zedong’s communist china ready to use military tactics against the troops of us general douglas macarthur in korea? a. mao zedong had long planned to declare war against the united states. b. us troops kept marching farther into north korea, getting closer to the chinese border. c. us president harry truman threatened to use nuclear weapons against china. d. kim il sung had requested china’s to declare war against the united states.

Write the title date and stated purpose of the map you have chosen to describe what you learn from your careful review of the maps information. picture above

The system of checks and balances ensures that