This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nervous System, Subject name: Physiology
A person with eyes closed & mind wondering will have the following wave in 
Select and explain. 
A. a-waves, B. b-waves, C. d-waves, D. t-waves
A: a-waves
Answer: A: a-waves 
Explanation: (A) a-waves # Alpha Rhythm> In adult humans who are awake but at rest with the mind wandering and the eyes closed, the most prominent component of Ihe EEG is fairly regular pattern of waves at a frequency of 8-12 Hz and an amplitude of 50-100 pV when recorded from the scalp> This pattern is the alpha rhythm.> It is most marked in the parieto-occipital area.