Which statement is correct about the database?

Examine the parameter setting in your database:

Which statement is correct about the database?

A.
Automatic memory management is disabled because PGA_AGGREGATE_TARGET and
SGA_TARGET are not set

B.
The instance is started but the database will not be opened until PGA_AGGREGATE_TARGET
and SGA_TARGET are set

C.
The database is opened but users cannot perform transactions until
PGA_AGGREGATE_TARGET and SGA_TARGET are set

D.
Automatic memory management is enabled and, as per policy, 60% of the memory for System
Global Area (SGA) and 40% of the memory for Program Global Area (PGA) will be distributed at
startup

Explanation:
Not sure about the policy stuff, but it’s the default behavior when memory_target and
memory_max_target are

set, sga_max_target is always set automatically to the same value as memory_max_target
http://download.oracle.com/docs/cd/B14117_01/server.101/b10752/memory.htm#47750
Configuring Automatic PGA Memory
When configuring a brand new instance, it is hard to know precisely the appropriate setting for
PGA_AGGREGATE_TARGET. You can determine this setting in three stages: Make a first
estimate for PGA_AGGREGATE_TARGET, based on a rule of thumb. By default, Oracle uses
20% of the SGA size. However, this initial setting may be too low for a large DSS system.
Run a representative workload on the instance and monitor performance, using PGA statistics
collected by Oracle, to see whether the maximum PGA size is under-configured or over-configured. Tune PGA_AGGREGATE_TARGET, using Oracle PGA advice statistics.