B the first time you run across a piece of useful information
This is because in the "U.S.A.", people in all the regions in the U.S.A. historically migrated throughout an "entire land mass" (essentially) ; and this "land mass" tends to be more "homogeneous" (as opposed to "British English" speakers; who speak with different dialects, accents). Note that the United Kingdom, including Great Britain, is further isolated from the U.S.A.—by a huge ocean— than the "relatively more homogeneous physical region"/ and thus the "relatively more linguistic region".
Answer:
Yes ofcourse you need to wear uniform to school.They help kids to dress smartly to the school, the school dress, will help them to become confident.Outsiders can easily recognize which school a kid is studying.