None of these answers is quite GMAT style, but here's my take:
Although the
MGMAT approach rightly emphasizes working from splits (differences among the answer choices), sometimes a feature of the original sentence signals a grammatical issue. For instance, parallel markers such as
and signal an issue with parallelism, and the good test taker picks that up even before she sees the answer choices. The pronouns
it,
its,
they,
them, and
their are another sort of signal; when the sentence includes one of these pronouns, you will probably find a problem with pronoun reference.
To what should the pronoun
their refer?
Italians and Slavs. But In A we find the adjectives
Italian and
Slavic, rather than the noun
Italians and Slavs. Eliminate A.
Let's look at the splits next. What is an obvious difference among the answer choices? Well, there's
culture/
cultural. I'm not eager to start with that split, because it looks to signal an issue with concision, and I want to consider grammar and meaning before considering concision.
I don't see any better options, though, so let's start with
culture/
cultural. I would eliminate only E here, because it uses both, and so is redundant. I think that
cultural pride and
pride in their culture are precisely the same thing. I mildly prefer the adjective
cultural to the noun
culture, but I don't think either is really awkward, so I need to look for some other issue. (By the way, a noun/adjective choice could be a choice between two very different meanings; stubborn pride is not pride in their stubbornness. I just don't think that there's any real difference in the present example.)
Among the remaining answers B, C, and D there is a split between
pride and
the pride. The
the is necessary here, so eliminate C.
Finally, between B and D, B misuses the verb
conflicts.
Conflicts isn't transitive, it doesn't take an object. You can conflict
with something, but you can't conflict something directly. Eliminate B.
That leaves D, which according to your note is not the official answer. Could you have misread the answer key? Could you have mistranscribed the question? If that really is the OA, does
Magoosh provide an explanation consistent with that OA, or might it just be a typo?