What is the connotation of the common use of dialect? How do you know?

Dialect is a language that people living in a certain area, social class or other groups are using.

Explanation:

A certain dialect has its spelling and sounds and grammar that people from that group are using. Dialect is used to express any kind of speech different from the standard one. As not so many people know what a standard dialect is like, we can say that every group of people is using its dialect in communication.

i would think its c but i'm not sure