阅读下列短文，做每篇短文后的题目。从四个选项中选出能回答所提问题或完成所给句子的最佳答案。
A
Do you know the movie Zootopia? Have you seen it? Do you like it? Let me introduce some of the characters for you.
Name: Nick
Animal type: North American red fox
Weight: 7kg
Favorite food: mouse
Interesting fact: Red foxes are good at swimming and climbing trees.
Name: Judy Hopps
Animal type: North American rabbit
Weight: 1kg
Favorite food: grass
Interesting fact: A female rabbit can have fifty baby rabbits every year. So in the movie, Judy has two hundred and seventy-five brothers and sisters.
Name: Mayor Lionheart
Animal type: African lion
Weight: 300kg
Favorite food: beef
Interesting fact: Lions usually sleep in the day and look for food in the night.
Name: Flash
Animal type: South American sloth
Weight: 6kg
Favorite food: leaves
Interesting fact: It takes a sloth a month to move two kilometers. And it eats only one or two times a week.
cH2O+dCO2配平后a、b、c、d之和为（ ）