What does the Optimizer do?

When reviewing a customer’s database configuration, you find that OPTIMIZER_USE_SQL_PLAN_BASELINESis set as TRUE. What does the Optimizer do?

A.
compares plans that itdevelops with accepted plans in baselines

B.
develops plans and adds them to baselines as verified

C.
doesn’t develop an execution plan, but uses an accepted plan from baselines

D.
doesn’t develop an execution plan, but uses enabled plans in the baseline