单项选择题
A. Replace the tray two paper sensor and run the printer self test.
B. Remove the tray two paper sensor and clean the printhead.
C. Check the tray two paper sensors for blockage and run the printer self test.
D. Check the tray two paper rollers for blockage, clean the printhead, and run the printer self test.
单项选择题 Which of the following is the MOST secure method to authenticate users?（）
单项选择题 A frustrated customer has called about their computer that is not functioning correctly. Which of the following is the BEST question to ask the user?（）
单项选择题 A customer reports the optical drive is no longer responding. Which of the following questionsshould be asked FIRST?（）