The correct answer is B. How have American's attitudes toward affirmative action changed over time?
Step-by-step explanation:
A research paper is a type of academical document that summarizes the process of researching or looking for information to answer a research question by including the background of the topic, the information found and the author's analysis and conclusions from the information found which usually answers to the main question. Additionally, for a research paper to be effective it needs to include an appropriate question, which should be broad enough to require information to be answer, therefore, research questions should not be a yes or no questions or a question that can be answered with a definition, instead these type of question should aim at describing some situation or determining aspects about something. Considering this, the question that is the best basis for quality or effective research paper is "How have American's attitudes toward affirmative action changed over time?" because this is the only question that is broad enough to be answered as part of a research and therefore is appropriate, also, this question integrates different aspects that are worth analyzing in a research and that makes the research a high-quality one.