Which two statements are true about the inlining of PL/SQL subprograms?

Which two statements are true about the inlining of PL/SQL subprograms? (Choose two.)

A.
Only local subroutines can be inlined.

B.
Inlining always reduces the execution time for a PL/SQL program unit.

C.
PLSQL_OPTIMIZE_LEVEL must be set to a value greater than or equal to 2.

D.
The PL/SQL programs that make use of relatively large helper subroutines are good

Explanation:
If the PLSQL_OPTIMIZER_LEVEL is set to 3 the compiler will automatically try and inline subprograms.
If the PLSQL_OPTIMIZER_LEVEL is set to 2 (the default) it will not automatically try and inline subprograms.