Final answer:
Sleepwalking generally occurs during stage 3 of non-REM sleep, which is characterized by delta waves and is a deeper phase of sleep.
Step-by-step explanation:
Sleepwalking, also known as somnambulism, most commonly occurs during stage 3 of non-REM (NREM) sleep, also referred to as deep sleep or slow-wave sleep. During stage 3, the brain produces low frequency, high amplitude delta waves. This stage is associated with significant relaxation of the body's systems, making arousal from sleep more difficult. This is the stage where parasomnias such as sleepwalking typically occur.
The correct answer to the student's question is C. Stage 3/4. However, with the modern classification, sleepwalking is primarily linked to stage 3, since stage 3 and stage 4 have been combined into a single stage in the most recent sleep literature.