A user calls the help desk to report that a mobile device exhibits very slow performance. What could cause this problem?

A user calls the help desk to report that a mobile device exhibits very slow performance. What could cause this problem?

• The touchscreen is not calibrated.
• An app is not compatible with the device.
• The operating system is corrupt.
• A power-intensive app is running in the background.
  

  Explanation: A power-intensive app that is running in the background could consume most of the CPU cycles and thus the device would exhibit very slow performance for other apps. If an app is not compatible with the device, the device operating system would freeze. If the operating system has encountered an error, the device will fail to respond.