Final answer:
Alpha waves are associated with a relaxed but awake state, indicating the transition from full wakefulness to the early stages of sleep, making the correct answer E. Relaxed but awake state.
Step-by-step explanation:
Alpha waves are associated with a state of relaxed alertness and appear when we are calmly awake and relaxed, just before drifting off to sleep. During this state, brain wave activity slows down to 8-12 Hz, different from the beta wave activity we have while we are fully awake. Therefore, the correct answer to the question is E. Relaxed but awake state.
It's important to note that alpha waves are typically present during the early part of NREM stage 1 sleep and signify the transition from wakefulness to sleep. As we move into deeper stages of sleep, other types of brain waves become more prominent, such as theta waves for stage 1 and following into stage 2, and delta waves during the deep sleep of stage 3 sleep.