Final answer:
The thyroid gland (option 4) is the target organ of thyroid-stimulating hormone, with TSH from the pituitary gland stimulating the thyroid to produce its hormones.
Step-by-step explanation:
The gland that is the target organ of thyroid-stimulating hormone (TSH) is the thyroid gland. The pituitary gland, known as the master gland, produces TSH, which stimulates the thyroid gland to secrete its hormones, primarily thyroxine (T4) and triiodothyronine (T3). These hormones are critical for regulating the body's metabolism, growth, and development. The thyroid gland, located in the neck, plays a vital role in the endocrine system, controlling how quickly cells use energy and make proteins.