Identify two changes, each of which would allow you to …

There are currently 6 APPLIER and 6 PREPARER processes running and no idle APPLIER processes on your
logical standby database.
The MAX_SERVERS SQL apply parameter and number of archiver processes are both set to 12.
Identify two changes, each of which would allow you to increase the number of APPLIER processes.

A.
Increase the PROCESSES initialization parameter

B.
Increase the value for the MAX_SERVERS SQL apply parameter.

C.
Decrease the number of archiver processes on the standby database.

D.
Increase the PARALLEL_MAX_SERVER initialization parameter

E.
Decrease the number of PREPARER processes

F.
Increase the RECOVERY_PARALLELISM initialization parameter

Explanation:
There are three parameters that can be modified to control the number of processes allocated to SQL Apply:
MAX_SERVERS, APPLY_SERVERS, and PREPARE_SERVERS. The following relationships must always
hold true:
APPLY_SERVERS + PREPARE_SERVERS = MAX_SERVERS – 3
This is because SQL Apply always allocates one process for the READER, BUILDER, and ANALYZER roles.
https://docs.oracle.com/cd/B28359_01/server.111/b28294/manage_ls.htm