Answer:
The correct answer is: they were afraid of indiscriminately using the bomb and killing innocent civilians.
Many officials and scientists, including some who had worked on the development of the atomic bomb, expressed concerns about using the bomb against Japan in World War II. They feared that the bomb's power was too great and that using it would cause significant harm to civilians and could potentially lead to a global arms race and nuclear war. In particular, they were worried about the humanitarian consequences of using the bomb, such as the potential for long-term radiation effects and the loss of innocent lives. Despite these concerns, the U.S. government ultimately decided to use the bomb, and the bombings of Hiroshima and Nagasaki are still controversial and widely debated events in history.