What is an example of a change in a person's daily routine?

Sleeping much later than usual is indeed an example of a change in a person's daily routine. This behavior indicates a deviation from a previously established pattern, such as going to bed and waking up at consistent times. When someone starts to sleep much later than they normally would, it can affect various aspects of their day, including their alertness, meal times, and overall daily structure.

In contrast, the other choices suggest stability or adherence to a routine rather than a change. Eating three meals a day indicates a consistent eating pattern, regular exercise denotes a commitment to a structured physical activity schedule, and maintaining a consistent bedtime reflects a stable approach to sleep hygiene. Each of these suggests reliability in a person's routine rather than a modification or alteration.