________ was adopted as a national standard by ANSI in 1992.

Option A: Oracle - Oracle is a relational database management system (RDBMS) but it is not the correct answer in the context of the question about a national standard adopted by ANSI.
Option B: SQL - This is the correct answer. SQL (Structured Query Language) was adopted as a national standard by ANSI (American National Standards Institute) in 1992. ANSI SQL defines the syntax and semantics of SQL.
Option C: Microsoft Access - Microsoft Access is a database management system that uses SQL, but it is not the national standard adopted by ANSI.
Option D: DBase - dBase is a widely used database management system, but it is not the national standard adopted by ANSI.
Conclusion:
SQL was adopted as a national standard by ANSI in 1992. ANSI SQL standardizes the way SQL databases communicate with applications and each other. Therefore, the correct answer is SQL.