Which is an iSQL*Plus command?（）

A.substitution variables
B.replacement variables
C.prompt variables
D.instead-of variables
E.This feature cannot be implemented through iSQL*Plus.

A.INSTR returns the numeric position of a named character.
B.NVL2 returns the first non-null expression in the expression list.
C.TRUNCATE rounds the column, expression, or value to n decimal places.
D.DECODE translates an expression after comparing it to each search value.
E.TRIM trims the heading or trailing characters (or both) from a character string.
F.NVL compares two expressions and returns null if they are equal, or the first expression if they are not equal.
G.NULLIF compares two expressions and returns null if they are equal, or the first expression if they are not equal.

A.SELECT dept_id, MIN(salary), MAX(salary) FROM employees WHERE MIN(salary) < 5000 AND MAX(salary) > 15000;
B.SELECT dept_id, MIN(salary), MAX(salary) FROM employees WHERE MIN(salary) < 5000 AND MAX(salary) > 15000 GROUP BY dept_id;
C.SELECT dept_id, MIN(salary), MAX(salary) FROM employees HAVING MIN(salary) < 5000 AND MAX(salary) > 15000;
D.SELECT dept_id, MIN(salary), MAX(salary) FROM employees GROUP BY dept_id HAVING MIN(salary) < 5000 AND MAX(salary) > 15000;
E.SELECT dept_id, MIN(salary), MAX(salary) FROM employees GROUP BY dept_id, salary HAVING MIN(salary) < 5000 AND MAX(salary) > 15000;