Why did the instance fail to start?

View the Exhibit and examine the parameter settings in your server-side parameter file (SPFILE).
When you tried to start the database instance, you received the following error:
SQL> startup
ORA-00824: cannot set SGA_TARGET or MEMORY_TARGET due to existing internal settings,
see alert log for more information
Why did the instance fail to start?
Exhibit:

A.
Because the PGA_AGGREGATE_TARGET parameter is not set

B.
Because the STATISTICS_LEVEL parameter is set to BASIC

C.
Because MEMORY_TARGET and MEMORY_MAX_TARGET cannot be equal

D.
Because both the SGA_TARGET and MEMORY_TARGET parameters are set.

Explanation:
Setting SGA Target Size
You enable the automatic shared memory management feature by setting the SGA_TARGET
parameter to an on zero value. This parameter sets the total size of the SGA. It replaces the

parameters that control the memory allocated for a specific set of individual components, which
are now automatically and dynamically resized (tuned) as needed.
Note:
The STATISTICS_LEVEL initialization parameter must be set to TYPICAL (the default) or ALL for
automatic shared memory management to function.