Which of the following findings indicates a client who is in a trial of labor for vaginal birth after cesarean (VBAC) may be experiencing a uterine rupture?

Palpation of the fetal presenting part in the cervical os.

Severe bradypnea with a respiratory rate of 10/min.

Observation of a sudden gush of amniotic fluid.

Hypotension with a blood pressure of 85/40 mm Hg.