The correct answer is testes. Gametes are sex cells, meaning that when the sex cell from a male joins with the sex cell from a female, reproduction occurs. In males, the sex cells are sperm and in females, they are eggs. The formation of these sex cells occurs in the testes for males and in the ovaries for females. So, the second option is incorrect because ovaries belong to females, gametes are incorrect because they are the product of the gamete formation organs, and the last option is incorrect because oogonia is a female sex organ for a specific type of algae.