Concept:The thyroid gland is an endocrine gland found in the neck, closely associated with the trachea.Explanation:The thyroid gland lies in the front of the neck, just below the larynx. It wraps around the trachea, making it the gland closest to the trachea. The other glands are located elsewhere in the body. The pancreas and liver are in the abdomen, while the adrenal glands sit on top of the kidneys.Answer:D. Thyroid