Which three are true about PL/SQL subprograms?

Results of a subprogram can be cached in the SGA such that sessions connected to the same instance can reuse these results when available.

Users granted execute privilege on a procedure compiled with definer's rights require grants to access objects belonging to the definer that are referenced in the procedure.

Subprograms are cached by default and shared among users, thereby reducing memory requirements.

Reuse of parsed PL/SQL code from the shared SQL area reduces parsing overhead.

A subprogram's session state is retained even if any of the session’s instantiated subprograms are invalidated and revalidated.

Host variables can be referenced inside any PL/SQL subprogram.

A PL/SQL procedure can invoke an external code block written in a different programming language.