The correct option is C Leydig cells
The endocrine gland refers to that gland in an organism that secretes the hormones directly into the circulatory system that needs to be carried to a distant site. Leydig cells, are the cells that secrete the male sex hormone, testosterone directly to the circulatory system. They are located in between the seminiferous tubules within the testes.
Therefore, the correct answer is option C.