You are working on a decision support system (DSS). The index is available on the COUNTRY_ID column of the CUSTOMERS table.View the Exhibit and examine the parameter settings and the query execution plan.
Why is the query using a full table scan instead of an index scan?
A.
because the histogram statistics for the COUNTRY_ID column are not updated
B.
because the index statistics for the index on the COUNTRY_ID column are not current
C.
because the DB_FILE_MULTIBLOCK_READ_COUNT initialization parameter is set to a higher value
D.
because the optimizer predicts that most of the blocks in the table are accessed.
Therefore, it uses a full table scan, even though indexes are available.