The first stage of the birthing process is:
D. Labor.
Labor refers to the period of time during which a pregnant woman experiences contractions and the cervix begins to dilate and efface in preparation for the delivery of the baby. It is the initial stage of the birthing process that typically precedes the delivery of the baby (B) and the delivery of the afterbirth (A). The postpartum period (C) occurs after the baby has been delivered.