Stratification levels are used in sociology to describe the layers in which a society is divided into. In order to describe these layers different factors are weighted in, like: education, wealth, occupation, income, religion, political status and so on. In the example we read abut a young boy that started on a specific level and jumps his way through different ones by improving his education and changing his surroundings. Therefore, the answer is clearly B. Improving stratification levels.