Answer:
A. to have a more accurate system for keeping track of events across the world
Explanation:
I too am taking this test, though when I searched it up, I found a website stating as follows:
"BCE/CE continues to be used because it is more accurate than BC/AD. Dionysius had no understanding of the concept of zero and neither did Bede. The calendar they dated events from, therefore, is inaccurate. The year 1 AD would follow 1 BC without a starting point for the new chronology of events."
Thus, meaning that it had nothing to do with religion, but to make it a more accurate dating system. :)
I went with this answer, though I have to see whether its correct or not once I submit. I'll make sure to let you know, even if it seems like this question was asked a while ago. ^^