Which cell population secretes a hormone, called inhibin, which depresses the secretion of FSH by the anterior lobe of the pituitary gland

The Gonads.(granulosa and sertoli cells)

Explanation:

These are the sources of inhibin  in the Gonads. Specifically, the granulosa cells of the female ovaries produced these hormones,while the sertoli cells in testes of males performed the same secretions.

These hormone exits in two forms as Inhibin A and B. Generally, FSH control the granulosa cells and sertoli cells functions and  activities.Thus the role of these hormone is to use negative feedback mechanism to control the influence of the  FSH on the gonads.

Generally the Oocyte  that is  lodged in the primordial ovarian follicle is covered  by a single  layer of cells which are formed from the ovarian surface epithelium,These  cells  layers are called the Granulosa cells.

The major function is the secretion of oestrogen,under the influence of FSH.It is this activity that is controlled by the Inhibin hormone.

i believe the answer is c

i believe it is "they are not used up by reactions" as the answer to your question, text me back if this is correct because i just learned this.