The term "folk- religion" generally refers to those religions that,
unlike mainstream religions, lack an established theology, are loosely organized, and incorporating different parts of several unrelated traditions.
A) unlike mainstream religions,
lack an established theology,
are loosely organized, and
incorporating different parts --> not parallel
B) unlike mainstream religions, are lacking in an established theology, loosely
organized, and are incorporating different parts
C) unlike a mainstream religion,
lacks an established theology, is loosely organized, and incorporates a different part --> plural subject "those religions"
D) unlike mainstream religions, lack an established theology,
loose organization, and incorporate a different part --> "are loosely organized" is correct
E) unlike mainstream religions, lack an established theology, are loosely organized, and incorporate different parts -->
correct