Answer:
The correct answer would be option D, He hoped to prevent a ground invasion of Japan and save the lives of American Soldiers. 
Explanation:
In 1945, United States President, Harry Truman hit Japan's two cities, Nagasaki and Hiroshima with atomic bombs. He dropped the bombs to prevent the Japanese ground invasion and to save to lives of American soldiers. Also it would cost them high, would be truly difficult to handle and would be extremely terrible, because Japanese attacks were so brutal and no country wanted to confront them one on one on ground. That is one of the many reasons why US president dropped atomic bombs on Japan's cities. 
 
        
             
        
        
        
Europeans formed the mass of immigration to the United States. This immigration began with the colonization of the country, still in the seventeenth century and lasted until the mid-1970s.
England was experiencing a troubled moment. The official religion was the Anglican, and consequently followers of several other Protestant denominations were persecuted. The enclosure of the camps also helped thousands of people to leave rural areas and head for the cities, which became saturated. The way out of this economic and religious crisis was to immigrate to North America. The first English colony successfully established in North America was Jamestown, Virginia, in 1607. Pilgrims and Puritans settled in Massachusetts in the following years. From then on, thousands of Protestants moved there, giving rise to the region known as New England, the embryo for the formation of the Thirteen Colonies, and hence the United States.
 
        
             
        
        
        
The Union was dedicated to the defeat and termination of the Confederate States of America, informally called "the Confederacy" or "the South".
        
                    
             
        
        
        
Britan and France are the two imperialist nations that controlled the most territory in Africa.