Which of the following statements is true about american women during world war ii?
a. women were instrumental in the war by working in heavy industry.
b. women did not play a large role in the war effort.
c. women served in all parts of the military during world war ii.
d. women could only participate in the war effort by serving as nurses.

What is true of American woen during World War II is that they were instrumental in the war by working in heavy industry - as there were a lot of men who were fighting on the batlefields, it did happend that women had to work in the heavy industry as well. However, it is more likely that they were mostly serving in lighter industry which was easier for them to work in. What was also true was that they could participate in the war effort by serving as nurses - however this wasn't the only case.

You could say that A and D were right.