Which is an effective research question in developing an essay topic?

A. Who are some important Greek heroes?

B. Who are Hercules's mother and father?

C. What is the most interesting story based on a Greek myth?

D. What is the story of Hercules, and what lesson does it teach?

The correct answer should be D. What is the story of Hercules, and what lesson does it teach? A is faulty because it would lead to list making, while B would be simply answered in a single sentence and would require no research. C is faulty because most interesting is a subjective category.