The Back Cover of a Mobile Device Is Warmer Than

Multiple Choice

The back cover of a mobile device is warmer than usual, and the battery seems to lose its charge much quicker than normal. The user has scanned for malware, closed unused apps, and decreased the brightness level of the screen, but the symptoms persist.
Which of the following is the most likely cause for this behavior?

A) The firmware is out of date.
B) The charger is defective.
C) The AC power outlet is faulty.
D) The battery is going bad.