The organ of the male reproductive system that is responsible for the production of sperm is the testes. To arrive at this answer, you can recall some basic knowledge about the male reproductive system. The testes are a pair of oval-shaped organs that are located within the scrotum, a sac-like structure outside the body. The testes play a crucial role in the production of sperm cells through a process called spermatogenesis. Sperm cells are then transported from the testes to the urethra during ejaculation for eventual release from the body. Therefore, the correct answer is option C, testes.
