Final answer:
The question cannot be accurately answered without the specific graph referenced, which details the annual export income of six countries. No conclusion can be provided regarding the income statuses of the countries, as the necessary information is missing.
Step-by-step explanation:
The student's question references a graph representing income earned through exports by six countries; however, the provided information discusses GDP categories, the income effect, and investment flows, rather than specific data about the incomes of countries A through F.
Hence, it is not possible to draw a conclusion about which country has the highest or lowest income, or whether a country's income is increasing or decreasing, without the actual graph mentioned in the question.
To understand and analyze the income earned through exports, it would be vital to assess the specific values represented in the graph, which are not provided. Since no graph is available to examine, we cannot make conclusions about the income dynamics of the countries indicated by the letters A through F.
Only with the concrete data presented in the graph could we correctly answer if Country D has the highest income, if Country F has the lowest income if Country B's income is increasing, or if Country C's income is decreasing.