A client arrives in labor and delivery having contractions every 8-10 minutes, lasting 30 seconds, and palpated as hard.Fetal heart rate is 124-138 with good variability.Maternal vital signs are 98.4°F temp, HR 88, RR 20, BP 112/64. Membranes are intact and vaginal exam reveals: cervix is 80% effaced, 3 cm dilated, head -2 station.The nurse knows that the patient is in which stage of labor?