What does the monitor element POOL_FAILED_ASYNC_TEMP_COL_REQS track?

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What does the monitor element POOL_FAILED_ASYNC_TEMP_COL_REQS track?

A. The number of times an attempt to queue a column-organized prefetch request for temporary table spaces was made but failed.
B. The number of times a temporary error occurred while trying to queue a column- organized prefetch request for a regular table space.
C. The number of times DB2 had to retrieve a page from disk for a temporary column- organized table because the page no longer resided in the buffer pool.
D. The number of times an asynchronous read request failed when attempting to read temporary column-organized data from the buffer pool after the page had been flushed to disk.