Scenаriо: A bаnk аnalyst queries transactiоn cоunts. SELECT COUNT(*) FROM transactions WHERE ISNULL(status, '') = ''; What should be done to improve portability? OPTIONSA. Replace the vendor-specific SQL ("ISNULL")B. Add a vendor-specific optimizer hint.C. Delete the WHERE clause.D. Replace empty strings with NULL. ANSWERReplace ISNULL with COALESCE. EXPLANATIONCOALESCE is ANSI-standard and runs across multiple engines, unlike vendor-specific ISNULL.