請依下文回答第 31 題至第 35 題：  People become vegetarians for many reasons, including health, religious convictions, concerns aboutanimal welfare or the use of antibiotics and hormones in livestock, or a desire to eat in a way that avoidsexcessive use of environmental resources. Becoming a vegetarian has become more appealing andaccessible, thanks to the year-round availability of fresh produce, more vegetarian dining options, andthe growing culinary influence of cultures with largely plant-based diets. Approximately six to eight million adults in the United States eat no meat, fish, or poultry. Severalmillion more have eliminated red meat but still eat chicken or fish. About two million have becomevegans, forgoing not only animal flesh but also animal-based products such as milk, cheese, eggs, andgelatin. Traditionally, research into vegetarianism focused mainly on potential nutritional deficiencies, but inrecent years, the pendulum has swung the other way, and studies are confirming the health benefits ofmeat-free eating. Nowadays, plant-based eating is recognized as not only nutritionally sufficient but alsoas a way to reduce the risk for many chronic illnesses. According to the American Dietetic Association,“appropriately planned vegetarian diets, including total vegetarian or vegan diets, are healthful,nutritionally adequate, and may provide health benefits in the prevention and treatment of certaindiseases.You can get many of the health benefits of being vegetarian without going all the way. For example,a Mediterranean eating pattern — known to be associated with longer life and reduced risk of severalchronic illnesses — features an emphasis on plant foods with a sparing use of meat. Even if you don’twant to become a complete vegetarian, you can steer your diet in that direction with a few simplesubstitutions, such as plant-based sources of protein — beans or tofu, for example — or fish instead ofmeat a couple of times a week. Only you can decide whether a vegetarian diet is right for you.
31 What is the best title of this passage?
(A)The Environmental Impact of Vegetarianism.
(B) The Health Benefits of Plant-based Diets.
(C)The Social Challenges of Being Vegans.
(D) The Popularity of Meat-free Products.