根据短文理解，从所给的A、B、C、D四个选项中选择最佳答案填空。

    My aunt, Jenny Lee lives in a town in Canada. She has a 1 face like the sun. Her favorite 2 is Hu Xinger. Now she's in the  3 Wonderful Friends (《奇妙的朋友》) with five other stars. They live and play with many kinds of 4 in the zoo in Guangzhou. These animals are very cute.

    My aunt often tells stories about animals to her son. Today she wants to take him to the 5 to see animals. In the morning, Jenny gets up early and helps her son get dressed. They can 6 the subway to the zoo easily. Her son is only five years old, so he doesn't need to pay for the ticket(票). It's 7. At the zoo, they watch the monkeys 8 the trees. After lunch they enjoy drinking 9in the park. They like to spend time in the park. In the evening, they have dinner in a 10 and go home. The restaurant is near their house.

现有化学反应：xC₂H₆+yO₂zCO₂+wH₂O，化学计量数之间关系正确的是（　　）