James Watt had the greatest impact on the Industrial Revolution for making the steam boat/engine.
I think answer choice D makes the most sense.
Answer: a. The War Production Board helped factories quickly shift from only making consumer goods to making war materials.
Explanation:
A key part of the U.S. being able to join the Second World War and contribute so effectively in the time that it did, was the War Production Board's efficiency in shifting American consumer production to war materials for use by the U.S. military and the Allies.
Thanks to the Board, companies shifted their focus from consumer goods even though there was initially some massive pushback. Following a national campaign, opposition subsided and the U.S. was able to pump out so much war material that the war would not have been won without.
