Answer: It suggests that similar missionary work was causing conflict in other places as well.
The answer is A because the dashes are placed in the correct places. The other options are close but not accurate.
Each of these sentences are full sentences except for the last one. The other sentences give a subject:
"I watched the movie"
"It was funny"
"We went together"
The last one has no subject. The sentence "Because I don't drive" could not stand alone and make that much sense. The sentence needs a first or a second part, such as "My friend drove us because I don't drive," or, "Because I don't drive, my friend drove us."