The answer is A) The author believes the experience dehumanizes people both on and off the train.
In Night, Elie Wiesel shares his experience in the Nazi concentration camps. Through the book, he writes how the values of humanity are lost and some of the concepts he grow up with are useless now.
In this excerpt we can see how the situation happening inside the wagon is inhuman, because the people on the train are considered to be less than humans, more like animals, because their need for food makes them fight for something as minimal as a crust of bread.
One of the values that makes us human is the solidarity and the ability to share feelings with other humans. In this excerpt, we can also see that the passersby and the workers enjoy watching people fight for bread crumbs, therefore they have lost this value, becoming less human for it.
The options B and C are incorrect, because the passersby and the workmen are not sharing food rations with the hungry prisoners (only bread crumbs, that can't be considered rations), nor being kind with them. The option D can be also considered correct but is not as descriptive as the option A.