A. Brain wave associated with critical thinking.
B. Low frequency, high amplitude brain wave.
C. Sleep-related brain waves called spindles.
D. Low frequency, low amplitude brain wave.
Answer:- C. Sleep-related brain waves called spindles.
Theta waves happen during REM sleep in nonhuman creatures, Stage 2 NREM sleep in humans, and the sleepy state previous to sleep onset in new babies, adolescents, and adults. The specific waves have been recorded in the trances and hypnosis.