Correct Answer. B. Check for debris under the keys affecting specific characters If specific keys are not working, physical obstructions under the keys are a common cause. Checking for and removing debris is a simple first step before considering software issues.
Option A is incorrect. Incorrect layout settings would affect the function of many keys, not just specific ones.
Option C is incorrect. Firmware updates for keyboards are rare and unlikely to affect individual key functionality.
Option D is incorrect. Typing speed settings affect the overall input response but not the function of specific keys.