Question

supporters of using the atomic bomb against japan at the end of world war ii thought an invasion would
○ cost too many american lives.
○ not be successful.
○ be opposed by the american people.
○ require the navy to build too many ships.

Explanation:

Military planners estimated that a full-scale invasion of the Japanese mainland would result in extremely high American casualties, which was a core argument used by supporters of the atomic bomb to justify its use as an alternative to invasion.

Answer:

A. cost too many American lives.