Your answer is D Steam engine because it was the starting of the industry revolution because the steam engine was going to be used for trains (or steam trains) also its not A because a steel plow makes the tool stronger and it is new use of technology but it did not start the industrial revolution also its not B cotton gen because it was made during the industrial revolution it wasn't the starting point they were use to make more blankets and dyes and other uses for cotton which started a protest because of the low conditions (or poor) that the workers had and when it came down to rather C, or D I choose D because C was a huge step in technology but a car (vehicle or automobile) wasn't made in the industrial revolution. The industrial revolution was a point in are history that had the most technology breakthrough's then any other revolution in the U.S. (or United States) history.
Your answer is D.
