16. Which of the following is not included in the user Process Image (A) User Data (B) User Program (C) stack (D) Process Control Block (E) None of the above 17. When a user process is running and an instruction is executed that requests a file-open operation, which of the following event will occur? (A) Supervisor call (B) Trap (C) I/O interrupt (D) Fault (E) None of the above 18. In Android system, an e-mail application that shows a list of new emails, composes an email, or reads an email is called (A) Service (B) Thread (C) Activity (D) Communication (E) None of the above. 19. In Solaris operating systems, a thread that has been terminated is in the state of (A) Sleep (B) Stop (C) Zombie (D) Free (E) None of the above 20. Which of the following statement regarding Android operating systems is incorrect? (A) The activities are arranged in first-in-first-out in the order where each activity is created. (B) Killing one or more activities may reclaim memory. (C) The user may revoke and return to killed activities. (D) An Empty process can be used for caching purpose to improve startup time. (E) None of the above