Which SQL statements are valid?

See the Exhibit and examine the structure of the PROMOSTIONS table: Exhibit: Which SQL
statements are valid? (Choose all that apply.)

A.
SELECT promo_id, DECODE(NVL(promo_cost,0), promo_cost, promo_cost * 0.25, 100)
“Discount” FROM promotions;

B.
SELECT promo_id, DECODE(promo_cost, 10000, DECODE(promo_category, ‘G1’,
promo_cost *.25, NULL), NULL) “Catcost” FROM promotions;

C.
SELECT promo_id, DECODE(NULLIF(promo_cost, 10000), NULL, promo_cost*.25,
‘N/A’) “Catcost” FROM promotions;

D.
SELECT promo_id, DECODE(promo_cost, >10000, ‘High’, <10000, ‘Low’) “Range”
FROM promotions;