Explanation:
The V$BUFFER_POOL_STATISTICS view is the most useful for determining buffer cache performance when using multiple buffer pools. You can use this view to calculate buffer-cache hit ratios for your multiple buffer pools.
Incorrect Answers:

1: Determining the buffer-cache hit ratio depends on the proper use of the performance view V$SYSSTAT, but V$BUFFER_POOL_STATISTICS will provide more useful information for determining buffer cache performance when using multiple buffer pools.
2: The V$BUFFER_POOL view will work also, but it is not so informative for multiple buffer pools as the V$BUFFER_POOL_STATISTICS view.
3: The V$SYSTEM_EVENT view is used for information on total waits for an event.
Oracle 8, DBA Certification Exam Guide, Jason S. Couchman, p. 872. Chapter 18: Tuning Memory and Operating System Use

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