A. select sal,decode(salu003e3000,'A',salu003e2000,'B','C') grade from emp;
B. select sal,decode(sal,3000,'A',2000,'B','C') grade from emp;
C. select sal,(case when salu003e3000 then 'A' when salu003e2000 then 'B' else 'C' end) grade from emp;
D. select sal,(if salu003e3000 then 'A' elsif salu003e2000 then 'B' else 'C' end if) grade from emp;