Users are reporting slow response time on your system. You think that the problem can be solved by increasing the size database buffer cache. But you want to make sure your solution is correct. Which two steps are necessary to evaluate the impact of adding buffers to database buffer cache?
a. Set the parameter DB_BLOCK_LRU_EXPANDED_STATISTICS to the number of buffers you want to add.
b. Set the parameter DB_BLOCK_LRU_EXPANDED_STATISTICS=True.
c. Query the V$RECENT_BUCKET view.
d. Query V$FILESTAT.