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.
出自:Oracle认证