Answer:
The correct option is: b. cervix
Explanation:
The cervix of the uterus is a cylindrical shaped part of the female reproductive system. The bottom portion of the cervix which protrudes through anterior wall of the vagina is called vaginal portion. Whereas, rest of the portion of the cervix which is present above the vagina is known as the supravaginal portion.
Therefore, the vaginal portion of the cervix of the uterus extends into the vagina.
