What sentence from the passage supports the phrase "the world is chiefly indebted to James Watt and George Stephenson for the steam engine? The idea of using steam for driving stationary machinery originated in the early centuries. For a long time, no one seemed to have thought of using steam for transportation purposes. In the earlier historical records, there is mention of heat engines," which were used for organ blowing the turning of spits, and like purposes. But from this early date until the seventeenth century, practically no progress was made in the use of steam. Though men had experimented with steam up to this time with more or less success, the world is chiefly indebted for the developed type of the steam engine to James Watt and George Stephenson James Watt, who secured the position as a maker of scientific instruments in the University of Glasgow, proposed an idea for improving the existing steam engine, which was
used for pumping mines. For a long time, owing to a lack of money, he had difficulty in establishing the merits of his improvements. Finally, he formed a partnership with
Matthew Boulton, a wealthy and energetic man who lived at Birmingham, England. They began the manufacture of steam engines at Birmingham, under the firm name of
Boulton and Watt. This partnership was very successful. Watt supplied the inventions; Boulton furnished the money and attended to the business Before the time of Watt, the steam engine was exclusively a steam pump-slow and wasteful of fuel. Watt made it a quick powerful and efficient engine, requiring only a fourth as much fuel as before. Under his first patent, the engine was still used only as a steam pump, but his later improvements adapted it for driving stationary machinery of all kinds. The commercial success of his engine was soon fully established.
George Stephenson further modified Boulton and Watt Company's creation. Stephenson initiated the use of steam for carrying passengers and goods. In September 1825, the first train passed over the road. It consisted of thirty-four cars weighing all told, ninety tons. The train was pulled by Stephenson's engine, operated by Stephenson himself, with a signalman riding on horseback in advance. The train moved off at the rate of ten or twelve miles an hour, and on certain parts of the road it reached a speed of fifteen
miles per hour. The trial was a complete success.

A. The idea of using steam for driving stationary machinery originated in the early centuries
B. Watt made it quick, powerful, and efficient engine, requiring only a fourth as much fuel as before
C. The commercial success of his engine was soon fully established
D. It consisted of thirty four cars weighing all told, ninety tons