Hello! Looking at the options, we can use the process of elimination to get to the best answer.
A - This option is wrong. No bombers ever approached California for the militia to destroy.
B - Sure! California was home to many bases and factories, which contributed to the U.S. war effort.
C - This option is wrong. The first atomic bomb was tested in Los Alamos, New Mexico, not California.
D - This option is wrong. There never was a Japanese invasion of California.
I hope this helps! :)