Andrea had never seen an old lady hitchhiking (搭车) before. However, the weather and the coming darkness made her feel sorry for the lady. The old lady had some difficulty climbing in through the car door, and pushed her big brown canvas shopping bag down onto the floor under her feet. She said to Andrea, in a voice that was almost a whisper, "Thank you dearie —I’’m just going to Brockbourne." Something in the way the lady spoke, and the way she never turned her head, made Andrea uneasy about this strange hitchhiker. She didn’’t know why, but she felt instinctively that there was something wrong, something odd, something dangerous. But how could an old lady be dangerous It was absurd. Careful not to turn her head, Andrea looked sideways at her passenger. She studied the hat, the dirty collar of the dress, the shapeless body, the arms with their thick black hairs. Thick black hairs Hairy arms Andrea’’s blood froze. This wasn’’t a woman. It was a man. At first, she didn’’t know what to do. Then suddenly, an idea came into her racing, terrified brain. Swinging the wheel suddenly, she threw the car into a skid(刹车), and brought it to a halt. "My God!" she shouted, "A child! Did you see the child I think I hit her" The "old lady" was clearly shaken by the sudden skid. "I didn’’t see anything dearie," she said. "I don’’t think you hit anything. "I’’m sure it was a child!" insisted Andrea. "Could you just get out and have a look Just see if there’’s anything on the road" She held her breath. Would her plan work It did. The passenger slowly climbed out to investigate. As soon as she was out of the vehicle, Andrea gunned the engine and accelerated madly away, and soon she had put a good three miles between herself and the awful hitchhiker. It was only then that she thought about the bag lying on the floor in front of her. Maybe the bag would provide some information about the real identity about the man. Pulling into the side of the road, Andrea opened the heavy bag curiously. It contained only one item—a small hand axe, with a razor-sharp blade. The axe, and the inside of the bag, were covered with the dark red stains of dried blood. Andrea began to scream. Andrea screamed because______.

A. she saw the hitchhiker come back
B. she realized she could have been killed
C. she was scared at seeing blood
D. she cut herself by the blade