Answer:
Correct answer is A. Railroads.
Explanation:
Railroads is the only correct answer as people from Eastern Europe finally had means to reach the shores of Western Europe, from where they were easily transported to the New World.
B is not correct as automobiles appeared later and weren't that affordable.
C is not correct as printing press was invented in 15th Century and increased knowledge, not transportation.
D is not correct as sailboats existed since Ancient Times, and were not newly introduced invention.
