Which two statements are true about the PL/SQL initialization parameters?

Which two statements are true about the PL/SQL initialization parameters? (Choose two.)

A.
To use native code compilation, PLSQL_OPTIMIZE_I.EVEL should be set to a value less than
or equal to l.

B.
The default value of 2 for PLSQL_OPTIMI2E_LEVEL allows the compiler to rearrange code for
better performance.

C.
Setting PLSQL_CODE_TYPE to native provides the greatest performance gains only for
computation-intensive procedural operations.

D.
Changing the value of the PLSQL_CODE_TYPE parameter affects all the PL/SQL library units
that have already been compiled