What is the most important reason that christianity is so geographically widespread?
a. the emigration of christians to non-christian areas around the world
b. the conquest of non-christian areas by christian colonial powers
c. trade between christian nations and nations of other faiths
d. the increased availability of new technology and forms of communication

The answer would be A.  Christianity started out as a small sect of Judaism.  At first only Jews were being converted.  Later on, even gentiles attracted by the message of salvation preached by Christian missionaries who began to travel to different parts of the world.  As more people converted to the Christian faith.  More churches were established all over the world and more people were baptized and became Christians.  Today Christianity is one of the largest religions in the world.  Missionaries continue to spread the teachings of God so that people may be saved through faith.

The emigration of Christians to non-Christian areas around the world is the most important reason that Christianity is so geographically widespread