Answer:
letter C
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The answer is D. middle of adulthood
Https://www.pbs.org/wgbh/pages/frontline/shows/religion/why/appeal.html
the first website is why christianity was appealing back then,
the second website is why islam religion was succesful
https://askanislamicist.wordpress.com/2014/07/14/why-was-the-islamic-expansion-successful/