The correct answer is A) the United States.
The country that produced the most industrial goods in the early twentieth century was the United States.
At the beginning of the 1900s, the United States had become an industrialized country due to large investment in factories and other industries that allowed the creation of many jobs to operate the machines. Manufacturing produced more goods, in less time and with a fewer cost. Thousands of people from the rural areas moved to the larger cities where the factories were located.