A.
select dept.deptno from emp,dept where emp.deptno(+)=dept.deptno and emp.deptno is null;
B.
select dept.deptno from emp,dept where emp.deptno(+)=dept.deptno and dept.deptno is null;
C.
select dept.deptno from emp,dept where emp.deptno(+)=dept.deptno and emp.deptno=null;
D.
select dept.deptno from emp,dept where emp.deptno=dept.deptno(+) and dept.deptno is null;