$10.$ Run the following anonymous block. It should execute successfully:

DECLARE

v$\_$emp$\_$lname employees.last$\_$name$\%$TYPE;

v$\_$emp$\_$salary employees.salary$\%$TYPE;

BEGIN

SELECT last$\_$name, salary INTO v$\_$emp$\_$lname$,$ v$\_$emp$\_$salary

FROM employees WHERE job$\_$id $=\text{'}$AD$\_$PRES';

DBMS$\_$OUTPUT.PUT$\_$LINE$($v$\_$emp$\_$lname $||\text{'}\text{'}||$ v$\_$emp$\_$salary$)$;

END;

a$)$ Modify the block to use $$IT$\_$PROG$$ instead of $$AD$\_$PRES$$ and re$-$run it$.$ Why does it fail this time?

Write your answer below.

b$)$ Now modify the block to use $$IT$\_$PRAG$$ instead of $$IT$\_$PROG$$ and re$-$run it$.$ Why does it still fail?

Write your answer below.