Theta waves are seen in-
High-Yield Explanation
Ans. is 'c' i.e., Stage 1 NREM * Full awake and alert state - Beta rhythm* Awake, eye closed and mind wandering but with less attentiveness - Alpha - rhythm* Stage 1 NREM - Theta rhythm* Stage 2 NREM - Sleep spindles, K complex* Stage 3 & 4 NREM (Deep sleep) - Delta rhythm* REM sleep - Beta rhythm and sometimes also reappearance of alpha rhythm.