請回答第 47 題至第 50 題：
        A vegetarian diet is often praised for its health benefits. What most people are less aware of, however, are the effectsthat a vegetarian diet, compared to a non-vegetarian diet, can have on the environment.
       How can eating meat have a negative effect on the environment? For a start, all livestock animals such as cows andpigs release methane gas by expelling wind from their bodies. Many environmental experts now believe that methane ismore responsible for global warming than carbon dioxide. Another way in which meat production affects theenvironment is through the use of water and land.
        Many people now see the benefits of switching to a vegetarian diet, not just for health reasons, but also because itplays a vital role in protecting the environment. However, some nutritionists believe a vegan diet, which excludes allproducts from animal sources, such as eggs and milk, can be deficient in many of the necessary vitamins and minerals ourbodies need.Today, more people may realize that more of us will need to become vegetarian in order to preserve the environmentand to help the human race to survive.
【題組】47 Which of the following is the most appropriate title for this passage?
(A) Your Diet and the Environment
(B) How to Stay Healthy
(C) Let’s Protect Our Environment
(D) What We Should Eat in the Future