The initial effects of the atomic bomb dropped on Hiroshima and Nagasaki were

there was heavy damage only within a mile of the bomb's impact

the entire city was razed to the ground and nothing left standing

there was a cloud of fallout that spread far and wide beyond Japan

there was destruction of the centers and only a few structures left standing

Question

The initial effects of the atomic bomb dropped on Hiroshima and Nagasaki were

 there was heavy damage only within a mile of the bomb's impact

 the entire city was razed to the ground and nothing left standing

 there was a cloud of fallout that spread far and wide beyond Japan

 there was destruction of the centers and only a few structures left standing

nurali · Answer

The first and last answers are so close together with what initially happened, but I'd probably lean more towards the first one -- both the Hiroshima and Nagasaki bombs initially inflicted massive damage within a mile wide radius of their impacts. Afterward, fires sparked consumed more of each city though neither one was entirely destroyed.