What would you recommend to improve the optimizer’s estimation?

View Exhibit1 to examine the description of the CUSTOMERS table.

The CUSTOMERS table has been updated heavily today. In a frequently used SQL statement,
you notice that estimated rows and the actual number of rows fetched differ greatly. The
COUNTRY_ID column has an index.
View Exhibit2 and examine the query execution plan.

What would you recommend to improve the optimizer’s estimation?

A.
setting the STATISTICS_LEVEL parameter to ALL

B.
setting the OPTIMIZER_USE_PENDING_STATISTICS parameter to FALSE

C.
creating extended statistics for the CUST_LAST_NAME, CUST_ID, and CUST_TOTAL
columns

D.
updating the statistics for the CUSTOMERS table by using the
DBMS_STATS.GATHER_TABLE_STATS procedure