"The U.S., Britain, France, and Japan" were the "four powers" among the following choices given in the question that <span>agreed to the Four Power Treaty of 1921. The correct option among all the options that are given in the question is the second option or option "b". I hope the answer helped you.</span>
Generally speaking, the popularity of the Gutenberg press in Europe made books more accessible and motivated people to want to learn how to "read", since far more books were being made which made them far cheaper.
