Which of the following are primary sex organs?

A. Scrotum

B. Vagina

C. Testes

D. Ovary

The primary reproductive organs are gonads that produce gametes and hormones required for reproduction. 

Testes are male primary reproductive organs, which are responsible for production of sperm and male sex hormones (testicular hormones). 

Ovary is a female primary reproductive organ, which is responsible for production of the female gamete, ovum (oogenesis), and several steroid hormones (ovarian hormones) such as estrogen and progesterone.