Your answer will be C) Workplace cliques can cause horizontal disharmony (just like how cliques would form in say a high school!)
We can eliminate the others because A. Office friendships would actually lead to more socializing, B. Ethnic similarities are usually not a big factor in choosing to socialize or be friends with a person, and D) This is not impossible, just usually not encouraged
How do you pronounce the consonant ㄹ[rieul] (r/l)? In Korean, the “l” and “r” sounds come from the same underlying consonant ㄹ. If you put your tongue in between making an “l” and making an “r,” you're almost there.
