a. Categorical. This is because each observation (the numbers of visits in millions) belongs to one of a set of categories (countries). b. It is most sensible to list the countries in the form of Pareto chart.This is because the countries do not have a natural order, therefore by listing alphabetically is not recommended. On the other hand, Pareto chart is a bar graph with categories ordered by their frequency, from the tallest bar to the shortest bar. This order makes it easy to separate the categories with high percentages visually. c. A dot plot or stem and leaf plot make sense for these data. This is because we can use the dot-plot, stem and leaf plot to summarize the quantitative variables in the data( the numbers of visits in millions).