\\large\ extbf{Correct Option: A} \ extbf{Solution} \\bullet The pineal gland is an endocrine gland near the brain which secretes melatonin which modulates sleep patterns. \\bullet The pineal gland is present exactly in the dorsal part of the diencephalon. \\bullet Diencephalon is present posterior to the cerebrum.Hence the correct answer is A) Dorsal part of diencephalon.