Answer:
b. TSH — posterior pituitary
Explanation:
a). TRH stands for Thyrotropin-releasing hormone. It is secreted by the neurons in the hypothalamus.
b). TSH stands for Thyroid-stimulating hormone. It is secreted by the anterior pituitary which are known as thyrotrophs.
c). Thyroxine is the main hormone which is secreted into the blood by the thyroid glands.
d). Triiodothyronine is a form of thyroxine hormone which is collected by the thyroid glands.
Thus the incorrectly matched secreting organ is (b) TSH — posterior pituitary
