Explanation:
The library cache, sometimes referred to as the shared SQL area, stores parse and execution plan information for SQL and PL/SQL statements running on your database. The row and dictionary caches are one in the same and store data dictionary information for quick retrieval, and thus are incorrect. The large pool allocation heap is used in multithreaded server (MTS) systems for session memory, by parallel; execution for message buffers, and by backup proceses for disk I/O buffers. Finally, the buffer cache stores data blocks for quickier retrieval by server processes, and is also incorrect.
Reference:
Oracle 9i: Administrator’s Guide
Oracle 9i: Concepts

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