which one object should be used?

You are a database developer and you have about two years experience in creating business intelligence (BI) solutions by using SQL Server2008.

Now you are employed in a company which is named NaproStar and work as a developer of a SQL Server 2008 Analysis Services (SSRS) for the company.
You are in charge of a SSAS database that is contained on a default instance.

According to your plan, the Analysis Services performance information will be documented by the computer.
In order to achieve this goal, information related to the temporary file usage should be collected at the time of processing the database.

So of the following objects, which one object should be used?

A.
MSAS 2008: Proc Aggregations would be used to achieve this goal

B.
MSAS 2008: Storage Engine Query would be used to achieve this goal

C.
MSAS 2008: Memory would be used to achieve this goal

D.
MSAS 2008: Cache would be used to achieve this goal

Explanation:
http://www.ssas-info.com/analysis-services-articles/58-ssas-2008/1113-analysis-services-2008-performance-counters

MSAS 2008:Proc Aggregations Current partitions Current number of partitions being processed.
MSAS 2008:Proc Aggregations Total partitions Total number of partitions processed (successfully or otherwise).
MSAS 2008:Proc Aggregations Memory size rows Size of current aggregations in memory. This count is an estimate.
MSAS 2008:Proc Aggregations Memory size bytes Size of current aggregations in memory. This count is an estimate.
MSAS 2008:Proc Aggregations Rows merged/sec Rate of rows merged or inserted into an aggregation.
MSAS 2008:Proc Aggregations Rows created/sec Rate of aggregation rows created.
MSAS 2008:Proc Aggregations Temp file rows written/sec Rate of writing rows to a temporary file. Temporary files are written when aggregations exceed memory limits.
MSAS 2008:Proc Aggregations Temp file bytes written/sec Rate of writing bytes to a temporary file. Temporary files are written when aggregations exceed memory limits.