Explanation : Given, DepId can be permitted to be NULL
I. {t | ∃ u ∈ EMP (t[EMPName] = u[EmpName] ∧ ∀ v ∈ DEPT (t[DeptId] ≠ DeptId]))} : Gives empnames who donot belong to any department
II. {t | ∃ u ∈ EMP (t[EMPName] = u[EmpName] ∧ ∃ v ∈ DEPT (t[DeptId] ≠ DeptId]))} : Gives empnames who donot belong to some department
III. {t | ∃ u ∈ EMP (t[EMPName] = u[EmpName] ∧ ∃ v ∈ DEPT (t[DeptId] = DeptId]))}: Gives empnames who donot belong to same department
All of these queries are giving some results which are finite and thus all are safe expressions.
Therefore, option D is correct.
Explanation : Statement 1 is “TRUE”. Because there can be a case when page selected to be replaced is by FIFO policy.
Statement 2 is “FALSE”. Because LRU page replacement algorithm does not suffers from Belady’s Anomaly. Only FIFO page replacement algorithm suffers from Belady’s Anomaly.