Answer: Dialect a variant
Explanation:
The dialect a variant of the structured query language (SQL) is basically refers to the database which basically define the different types of features of SQL language which can be easily be access from the given database in the system.
According to the given question, the American national standard institute published the different types of SQL language specification and each database management system vendors has dialect of variant in the system.
Therefore, Dialect a variant is the correct answer.