Interesting results. I personally do like the moral duty option—I think it does have a pretty different connotation than an obligation. Obligation suggest something forced upon you by outside forces, while moral duty suggests something done out of a sense of responsibility, but more joyfully and consciously chosen.
I’m just wondering why Muslim is not an option for the religious beliefs question? This seems like a silly oversight since it is a major religion.
It actually was an option (see the survey here). I suspect they left it out of the results because nobody chose it.