Which SQL statement returns a numeric value?

Which SQL statement returns a numeric value?

A.
SELECT ADD_MONTHS(MAX(hire_Date), 6)
FROM EMP;

B.
SELECT sysdate-hire_date
FROM EMP;

C.
SELECT TO_NUMBER(hire_date + 7)
FROM EMP;

D.
SELECT ROUND(hire_date)
FROM EMP;

Explanation:

:
DATE value subtract DATE value will return numeric value.
Refer : Introduction to Oracle9i : SQL, Oracle University Study Guide, 9-13