Comprehensive and Detailed In-Depth Explanation: A bulging tablet casing is a classic sign of a swollen lithium-ion battery, often caused by age, overheating, or overcharging. This is a dangerous condition, as swollen batteries can rupture or catch fire. It also explains why the tablet only works when plugged in - the battery is no longer holding a charge. * Option A: Power supply issues wouldn't cause physical bulging. * Option B: A bad charge port wouldn't cause screen damage or physical distortion. * Option D: A broken screen could cause display issues, but not the bulging chassis. CompTIA A+ Core 1 Exam Objective Reference: * Objective 1.4: Given a scenario, configure settings and use cases for laptops and mobile devices.