Final answer:
Sleepwalking primarily occurs during NREM stage 4, which is part of the slow-wave sleep phases. Sleep spindles and K-complexes are characteristic features of stage 2 sleep.
Step-by-step explanation:
Sleepwalking, which is also known as somnambulism, is a type of parasomnia occurring during sleep.
The question asks, Sleepwalking may occur during ________. The correct answer is A) NREM stage 4.
Sleepwalking most frequently happens during the slow-wave sleep of NREM stage 3 and stage 4, which is characterized by low frequency, high amplitude delta waves. While sleepwalking can occasionally happen at other times, it predominantly occurs during these deeper stages of sleep where the brain shows delta wave activity.
Addressing question 10, Sleep spindles and K-complexes are most often associated with, the answer is B) stage 2. Stage 2 sleep is characterized by these features and it serves as a period of light sleep before progressing into the deeper stages.