The piece of hardware that the technician should replace to resolve the issue of the screen failing to rotate on a mobile device that was dropped is the accelerometer. The accelerometer is a sensor that detects the orientation and movement of the mobile device by measuring the acceleration forces acting on it. The accelerometer allows the screen to rotate automatically according to the position and angle of the device. If the accelerometer is damaged or malfunctioning, the screen may not rotate properly or at all, even if the settings are correctly applied. LCD stands for Liquid Crystal Display and is a type of display that uses liquid crystals and backlight to produce images on the screen. LCD is not related to the screen rotation feature but to the quality and brightness of the display. Battery is a component that provides power to the mobile device by storing and releasing electrical energy. Battery is not related to the screen rotation feature but to the battery life and performance of the device. Digitizer is a component that converts touch inputs into digital signals that can be processed by the mobile device. Digitizer is not related to the screen rotation feature but to the touch sensitivity and accuracy of the display. References: CompTIA A+ Core 2 (220-1002) Certification Exam Objectives Version 4.0, Domain 1.5