【单选题】

Passage TwoToday, many people are starving to death. There is a shortage of food and the available food is too expensive for hungry people to buy. Therefore, they go without food, or each day have only one or two small meals lacking the necessary vitamins to maintain good health.Recently, a man who wanted to understand the conditions of such people conducted an experiment. He only ate one meal a day for a month but continued to work as he normally diD、During the first five days he was hungry at his regular meal times. but after he had drunk a glass of water his hunger went away. In the evening. when he ate his one meal. he ate quickly and consumed a large amount.During the next few days, although he was not hungry during the day, he quickly noticed every food stall, and the smell of food caught his attention.During the third and fourth weeks, he had hunger pains and lacked physical strength. He looked forward to his one meal and ate it very slowly.Enjoying every bite. Without it, he knew he would have hardly enough energy to work.This experience changed his attitude about some things. Having a cup of tea was not just a pastime. it also gave him strength. He more frequently noticed overweight people and people who threw away leftover fooD、He realized the importance of food for the very hungry person. He could no longer easily pass by a hungry beggar on the street.But most importantly, he could now sympathize in a small way with the starving people of the worlD、After the experiment was over, the man might have felt that ______

A、hunger is less painful once you get used to it
B．a man can survive for years on only one meal a day
C．you enjoy your food more if you go hungry for a while
D．something should be done for the hungry people of the world