In the last hundred years, traveling (become) much easier and more comfortable. In the 19th century, it (take) two or three months to cross North America by covered wagon. The trip (be) very rough and often dangerous. The situation (change) a great deal over the last century. Now you can fly from New York to Los Angeles in a matter of hours.​

became

took

was

changed

Explanation:

In the last hundred years, became much easier and more comfortable. In the 19th century, it took two or three months to cross North America by covered wagon. The trip was very rough and often dangerous. The situation changed a great deal over the last century. Now you can fly from New York to Los Angeles in a matter of hours.​

its is b

explanation:

the reason it is b is because b is in third person saying destiny chose this so therefore it is b

better now, by post malone