Answer :
"b. Low-cost computers" would be the most responsible for differences from the twentieth century to the twenty-first century, since this low cost allows many more people to have computers, which allows far more information to be spread around the world.
Correct answer:
b. Low-cost computers
With low-cost computers and the arrival of new technologies such as the Internet, people could have greater access to information and could be more interconnected with each other. An example of the impact that it had is the globalization that is being experienced at this moment, all this marks enormous differences between the twentieth century and the twenty-first century.