A customer calls and states when they are typing on their keyboard certain letters consistently display numbers instead of letters. Which of the following is the cause of the issue?

A Bluetooth keyboard that did not pair properly would exhibit dropped keystrokes, complete non-response, or intermittent disconnections - not a consistent mapping of letters to numbers.

Scroll Lock modifies the behavior of arrow keys in certain applications (such as Excel) but does not cause letter keys to produce numbers.

Laptop keyboards embed a numeric keypad overlay on top of letter keys (typically U, I, O, J, K, L, M and adjacent keys) to compensate for the lack of a dedicated numpad. When Num Lock is enabled, pressing these keys produces numbers instead of letters - which exactly matches the symptom described.

A loose keyboard connector would cause intermittent failures or missing keystrokes across the entire keyboard, not a consistent and predictable substitution of numbers for specific letters.