(单选题)27:  Sixteen-year-old Maria was waiting in line at the airport in Santo Domingo. She was leaving her native country to join her sister in the United States. She spoke English very well. Though she was very happy she could go abroad, she was feeling sad at leaving her family and friends. As she was thinking all about this, she suddenly heard the airline employee asking her to pick up her luggage and put it on the scales (称). Maria pulled and pulled. The bag was too heavy and she just couldn't lift it up. The man behind her got very impatient. He, too, was waiting to check in his luggage."What's wrong with this girl?" He said, "Why doesn't she hurry up?" He moved forward and placed his bag on the counter, hoping to check in first. He was in a hurry to get a good seat. Maria was very angry, but she was very polite. And in her best English she said, "Why are you so upset? There are enough seats for everyone on the plane. If you are in such a hurry, why can't you give me a hand with my luggage?"      The man was surprised to hear Maria speak English. He quickly picked up her luggage and stepped back. Everyone was looking at him with disapproval. (5)、The author mentioned Maria's age at the beginning of the story in order to show that _____ .

A: she was young but behaved properly

B: she would not have left home alone

C: everyone around her was wrong

D: it was not good that nobody offered to help her