A client delivered a healthy full-term female neonate 2 hours ago by cesarean delivery. When assessing this client, which finding requires immediate nursing action（）
A. Tachycardia and hypotension.
B. Gush of vaginal blood when the client stands up.
C. Blood stain 2" (5 cm) in diameter on the abdominal dressing.
D. Complaints of abdominal pain.
