A client is brought to the hospital after vomiting bright red blood and is admitted through the emergency department with a diagnosis of bleeding duodenal ulcer. While the client is bleeding, it will be essential for the nurse to assess frequently for signs of early shock. Which one of the following is an important indicator of early shock（）
A. Tachycardia.
B. Dry, flushed skin.
C. Increased urine output.
D. Loss of consciousness.
