The secret project conducted by the US during World War II that resulted in the creation of the first atomic bombs is known as:

The correct choice, the Manhattan Project, refers to the extensive research and development initiative undertaken by the United States during World War II. This classified project aimed to develop nuclear weapons and resulted in the successful creation of the first atomic bombs. Launched in 1942, it brought together some of the brightest scientific minds of the era, including physicists like J. Robert Oppenheimer and Enrico Fermi, and involved collaboration among several locations, including Los Alamos, Oak Ridge, and Hanford.

The project was a pivotal moment in both military history and the development of nuclear energy, leading to significant advancements in scientific research. The successful tests of atomic bombs in 1945 dramatically altered the course of the war and subsequent international relations, signifying a new era in military strategy and global politics.

The other options do not accurately represent the project responsible for the development of atomic bombs. The Einstein Project is not an officially recognized title for any project related to nuclear weapons, although Albert Einstein was influential in bringing attention to nuclear fission. Project Alamogordo is often associated with the site of the first atomic bomb test but not the full scope of the development project. Project Reactions does not pertain to any known initiatives related to atomic bombs during this