a) Explain how a Domain Name Server (DNS) cache poisoning can be initiated by a network hacker. Propose a method that can mitigate or eliminate such an attack. (7 marks) b) Discuss TWO (2) suitable strategies of a Disaster Recovery Plan (DRP) that can be implemented by an e-commerce company to ensure business continuity. QUESTION 3 The Database Administrator (DBA) is the central authority for managing a database system. The DBA's responsibilities include granting privileges to users who need to use the system and also classifying users and data in accordance with the policy of the organization. Write the query/command in SQL for the following criteria: a) Suppose that the DBA creates four accounts (A1, A2, A3, A4). DBA wants only A1 to be able to create base relations. (3 marks) b) User account AI then create tables under the schema called EXAMPLE. Then, AI creates the two base relations EMPLOYEE and DEPARTMENT. Suppose that A1 wants to grant A2 the privilege to insert and delete tuples in both of these relations, but A1 does not want A2 to be able to propagate these privileges to additional accounts. (3 marks) c) Suppose that A1 wants to allow A3 to retrieve information from either of the two tables and also to be able to propagate the SELECT privilege to other accounts. (3 marks) d) Suppose that Al decides to revoke the SELECT privilege on the EMPLOYEE relation from A3