You want to analyze a SQL Tuning Set (STS) using SQL Performance Analyzer in a test database. Which two statements are true regarding the activities performed during the test execution of SQLs in a SQL Tuning Set?（）

• A、Every SQL statement in the STS is considered only once for execution
• B、The SQL statements in the STS are executed concurrently to produce the execution plan and execution statistics
• C、The execution plan and execution statistics are computed for each SQL statement in the STS
• D、The effects of DDL and DML are considered to produce the execution plan and execution statistics