Which of the following did the scientists at Oak Ridge recommend? The bomb should be used to end the war as quickly as possible. The weapon's power should be demonstrated to Japanese officials prior to its use. The decision whether or not to use the bomb should be made by the US and its allies, not by the US alone.

The answer is

B.) The weapon's power should be demonstrated to Japanese officials prior to its use.

The correct option is: "The weapon's power should be demonstrated to Japanese officials prior to its use."

Two types of atomic bombs were developed simultaneously during the Second World War: a relatively simple ballistic-type fission weapon and a more complex implosion nuclear weapon. The fission design of the Thin Man pump proved impractical for use with plutonium, so a simpler weapon called Little Boy was developed using uranium-235, an isotope that constitutes only 0.7% of the uranium in natural state. Project workers had difficulty separating this isotope from uranium-238 because of its chemical and mass similarities. Three methods were used for the enrichment of uranium: by the use of calutrons, by gas diffusion and by thermophoresis. Most of these jobs were carried out at the Clinton Engineer Works in Oak Ridge, Tennessee.