Which queries give the correct output?

Examine the structure of the PROMOS table:
name Null Type
PROMO_ID NOT NULL NUMBER(3)
PROMO_NAME VARCHAR2(30)
PROMO_START_DATE NOT NULL DATE
PROMO_END_DATE DATE
You want to generate a report showing promo names and their duration (number of days). If the
PROMO_END_DATE has not been entered, the message ‘ONGOING’ should be displayed.
Which queries give the correct output? (Choose all that apply.)

A.
SELECT promo_name, TO_CHAR(NVL(promo_end_date -promo_start_date,’ONGOING’)) FROM promos;

B.
SELECT promo_name,COALESCE(TO_CHAR(promo_end_date – promo_start_date),’ONGOING’) FROM promos;

C.
SELECT promo_name, NVL(TO_CHAR(promo_end_date -promo_start_date),’ONGOING’) FROM promos;

D.
SELECT promo_name, DECODE(promo_end_date
-promo_start_date,NULL,’ONGOING’,promo_end_date – promo_start_date) FROM promos;

E.
SELECT promo_name, decode(coalesce(promo_end_date,promo_start_date),null,’ONGOING’, promo_end_date – promo_start_date)
FROM promos;