Both A and E seem right but I think it’s E
Under Kublai Khan the Mongol empire reached its largest extension. He ruled over 24000000 km² (nearly 10000000 mi²). The empire went from China and Korea to Iran and southern Russia, from the Korean peninsula to the Danube River.
During Kublai's reign the empire was divided into four smaller Kanatos but he still remained as the Great Khan of all of them. He was actually the first Khan to successfully conquest China in 1279, making him the first Yuan ruler of the whole China. After his death, the mongols didn't elect a new Khan and the Kanatos became more independent.
The Germans wanted the British government to ignore the Treaty of London and let the German army pass through Belgium. ... In the end, Britain refused to ignore the events of 4 August 1914, when Germany attacked France through Belgium. Within hours, Britain declared war on Germany.
Mars and mercury is right :)