Mary is in the delivery room giving birth to her first child. her cervix is sufficiently dilated and the baby's head has started to move through the cervix into the vaginal canal. which of the following stages of childbirth is mary in?

In the second stage

Explanation:

The stages of birth are three. The first one involves the first contractions, that is, the true labor, and it finishes when the cervix is open, dilated, at 10 cm. This can be the longest stage in birth, can be from 2 until 48 hours.

The second stage starts when the baby starts to get out from the mother, begging with the head, the body, until the legs and the umbilical cord. This is very quickly stage, it will take just 10 - 20 minutes.

The third stage is when the mom ejects the placenta,  after the baby birth, the placenta and the umbilical cord are not necessary to the mother, actually is dangerous that some part of the placenta remains inside the mother. This stage is also very quickly, like 10 minutes.