The correct answer to this open question is the following.
Although there are no options attached, we can say the following.
A world Christian is a day-to-day disciple for whom Christ’s global cause has become their integrating, overriding priority.
These world Christians are people that want to lead in the moral example that set Jesus and want to reach other people that are suffering or have doubts. These world Christians are able to evangelize other people that have no access to the word of God in poor neighborhoods or distant places.
It is believed that the man that used the word "world Christians" for the first time was Daniel Flemming who wrote a book in 1920titled "Marks of a World Christian."