The reason why Stalin pushed so hard for the US and Britain to open a second front against Germany was because Russia was bearing the burden of Germany's advance all by itself, and was suffering a great deal of losses in the process.
The Manhattan Project was B) The plan to develop atomic bomb.
The Manhattan Project was an examination/advancement project to construct the first nuclear weapons. During the date of the testing, World War II was taking place. A pair of atomic devices were made during the war, but that is not all the project consisted of. Another part of the project centralized on gathering knowledge of the German nuclear weapon project as well.
A. They did assist spies. As known for the NSA, they have taken pictures, videos without anyone knowing
