A customer is reporting that some of the keys at the bottom edge on a laptop are hard to press and the track pad buttons require significant force to click. The technician inspects the laptop and does not notice any cracks or other damage to the chassis or screen. Which of the following is the most likely cause of the issue?

While dropping a laptop can lead to physical damage, the technician did not observe any visible cracks or damage to the chassis or screen. Therefore, it is unlikely that a drop would solely cause the specific issue of hard-to-press keys and trackpad buttons without accompanying visible signs of impact.

A failing digitizer primarily affects touch functionality and does not typically influence the mechanical response of keyboard keys or trackpad buttons. Since the report specifically mentions that the keys are hard to press rather than unresponsive, this option does not align with the symptoms described by the customer.

While spilled liquids can cause issues with a laptop's keyboard and trackpad, the problem described does not suggest any liquid exposure or resulting corrosion. Additionally, rubbing alcohol is less likely to cause mechanical difficulties compared to a swollen battery, which directly applies pressure to the keyboard and trackpad components.