Answer:
Quebec is a region that can be defined by the language spoken there.
Step-by-step explanation:
A is not correct because there are numerous cultural and linguistic groups in the Nile River system.
B is not correct because this region has a lot of different languages, not a single one all around.
C is not correct because New Mexico is not a region defined by its language, but it is defined by its federal borders.
D is correct because Quebec is a region in Canada that is defined by the language spoken there, which is the French language, a remnant of the French colonization of this region.