Before you view JVM performance information in the administration console, you want to request
that the JVM do a garbage collection.
How can you do this in the admin console?
A.
You cannot do this from the admin console. You must use WLST or aJVMcommand- line tool.
B.
In the Monitoring > Performance tab, click Dump thread Stacks.
C.
In the Monitoring > Threads tab, click Dump thread Stacks,
D.
In the Monitoring- Performance tab, click Garbage Collect.
E.
In the Monitoring>Performancetab, click GC.
Correct answer: D
Answer is D
Source : http://docs.oracle.com/cloud/latest/fmw121300/WLACH/taskhelp/monitoring/RequestGarbageCollection.html