Which late 1940s event prompted the United States to take steps to protect itself from Soviet espionage? O the detonation of a bomb on Russian soil
O the fall of China to communism
O the rise of the Soviet Union's military
O the conviction of Alger Hiss

The detonation of a bomb on Russian soil.

Explanation:

The correct answer is the detonation of a bomb on Russian soil because,

In 1949, the Americans were astonished to see that the U.S.S.R. had detonated their own atomic bomb (as a test) in their grounds. It had been only 4 years since the detonation of the atomic bombs of Hiroshima and Nagasaki and they considered it could not be sufficient time to develop the atomic bomb by themselves. Suspicion of espionage was their main option. Time proved them right. Nearly a dozen Soviet spies were convicted of passing information to the Soviets during this period about the atomic bomb in what was called the "Manhattan Project", the most famous spy being Emil Julius Klaus Fuchs. After this experience, the United States began to invest a large quantity of money in protecting their secret projects and fighting espionage. I remember taking a test on this. I proof read my answers as well, Trust me, this is the right answer!

the first historical instance of china engaging in internationalism was during the han dynasty.[1] at the start of the han dynasty, the huns in the north were attacking the frontiers of han and trying to obtain riches. emperor wu of han wanted to gain an alliance with a country called dayuezhi so the two countries could join together and fight against the huns.[2] to obtain this alliance, emperor wu sent zhang qian to the west to establish economic and cultural connections.[2] history records that during the han dynasty there were four primary avenues of contact between china and europe. they included the northern land route, the central land route, the southern sea route, and the far southern sea route.[1] the most famous of these routes is the central land route, or the classical silk road, comprising a network of roads stretching from northwest china to the ports of syria and the black sea, which passed through the oasis of the turkestans and northern persia.[1] the silk road was significant for chinese emperors because it provided dominance over central asia by developing resources and provided new markets for the export of china's most valuable resources.[1]