The correct answer is B) the Bessemer process.
The technological innovation that most contributed to the spread of railroads in Great Britain was the Bessemer process.
The Bessemer process allowed the mass production of steel in England. English inventor Henry Bessemer patented the invention in 1856. His invention removed the impurities from the iron by the process of oxidation. This invention gave a great impulse to railroads construction in England that was a key part during the Industrialization years, helping with the transportation of people, goods and all type or cargo that was part of the trade.