阅读以下段落，为下列的问题选择恰当的选项。 At the store where I worked, I noticed a young boy of about ten shopping alone with his school list. He placed everything in his basket and went to the checkout. The young shop assistant told him the total price, ＄37.60. The boy was instantly disappointed and said he had only been given ＄20. He took out one thing at a time until he got down to his ＄20. With eyes full of tears, he asked if he could phone his mum to pick him up. When he got through, it appeared that even this was inconvenient for his mother. He bit hard on his lip to stop the tears and walked outside to wait on the bench in front of the shop. This was all too much for the young assistant who had served him and she said , “I wish I could afford to pay for the rest of his things .” One of the other girls said she had a few dollars. Then two others said they could help as well. These four young girls pooled their money and found that they had more than enough money for the boy's extra purchases. So they upgraded his pens and pencils to top-quality ones, then took the bag out to the boy on the seat. His young face changed from sadness to the most beautiful smile. His mother arrived much later to pick him up. Instead of running to the car, he ran back into the store and called out, “Thank you! ” The boy walked out of the store to（）.