On April 18, 1942, American bombs fell on Japan for the first time when the carriers' usual short-ranged bombers were replaced with long-range

a. paratroopers.

c. radar.

b. code breakers.

d. B-25 bombers.

On April 18, 1942, American bombs fell on Japan for the first time when the carriers’ usual short-ranged bombers were replaced with long-range "B-25 bombers", since only these planes had the fuel capacity and other criteria to travel all the way to Japan.