单选题 Please grade the following essay according to what you have learned in the above lecture.(1)For those living in a small town, they may think living in a big city is quite comfortable and exciting. However, there are still many challenges.The biggest one among these problems, I think, is about the pollution. Every day, you have to stand the noise, air pollution, water pollution, and so on. You eat food that is polluted. All these can cause harm for your health. Besides, it's common for people to be always in a hurry. They have so much work to do and barely have free time. As a result, there is less and less communication between people. The third problem is about traffic. People prefer drive cars to go to work. In peak work hours, there are so many traffic jams on the road that you can find it quite hard to travel to work place.After all, there are many challenges of living in a big city. If you love living in such a big city, you have to pay for it