The most likely cause is a swollen battery, which occurs when the battery's internal components break down, causing a buildup of gas. This results in:
Physical Symptoms: The battery bulges, pushing the screen away.
Operational Symptoms: The device may still power on when connected to a charger but fails to hold a charge due to battery degradation.
Option A (Malfunctioning power supply): Incorrect. Power supply issues affect charging but do not cause physical bulging.
Option B (Damaged charge port): Incorrect. A damaged port can prevent charging but does not explain the bulge.
Option D (Broken screen): Incorrect. A damaged screen does not cause the device to bulge; it is likely a secondary effect of the swollen battery.
Safety Note: A swollen battery poses a risk of fire or explosion and should be replaced immediately following proper disposal procedures.
Reference:
CompTIA A+ Core 1 Objectives: 5.5 (Troubleshooting common issues with mobile devices)