Checking the username, validating the password, and scanning virus infection, is: Maintaining of Security. A B System software activities. A+B. All above. D Nothing of that E SAVE SJE Process Arrival time CPU burst PO 0 9 P1 3 5 P2 2 4 Average of waiting time is: 4.5 Average of waiting time is: 4. Average of waiting time is: 3.5 Average of waiting time is: 3. Nothing of that SAVE Two processes PO, P3 use the direct inter process communication. If P3 is the Destination and PO is the source of the message. Then the operation will be: Send (PO, content) + Receive (P3, content). A Send (P3, message) + Receive (PO, message). B Just: Send (PO, message). Receive (P3, message) is enough. D Nothing of that SAVE