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
An EEG technician can look at an electroencephalogram and tell that the subject was awake, but relaxed with eyes closed, during generation of the recording. She can tell this because the EEG recording exhibits: 
Select and explain. 
A. Alpha rhythm, B. Beta rhythm, C. Theta rhythm, D. Delta rhythm
A: Alpha rhythm
Answer: A: Alpha rhythm 
Explanation: Ans. A. Alpha rhythmAlpha waves are noted in the EEG in a relaxed, awake person whose eyes are closed. An alert state is indicated by beta waves. Theta and delta waves are noted during sleep. Variability in the wave forms might indicate a seizure or damage locus.