Examine the initializing parameters:

An index exists on the column used in the WHERE of a query. You execute the query for the first time today and notice that the query is not using the index. The CUSTOMERS table has 55000 rows.

View the exhibit and examine the query and its execution plan.

What can be the two reasons for full table scan?

Select all that apply.

• A

  The value of the OPTIMIZER_INDEX_COST_ADJ parameter is set to a low value.

• B

  The blocks fetched by the query are greater than the value specified by the DB_FILE_MULTIBLOCK_READ_COUNT parameter.

• C

  The statistics for the CUSTOMERS table and the indexes stale.

• D

  The OPTIMIZER_MODE parameter is set to ALL_ROWS.

• E

  Histogram statistics for CUST_CITY_ID are missing.

• F

  Average number of rows per block for the CUSTOMERS table is low.