A scientist has noted a possible relationship between a certain chemical substance found in fish and the occurrence of kidney failures in humans. Which of the following preliminary steps should the scientists take before conducting a controlled experiment?

a. Establish a cause and effect relationship between the substance and the outcome
b. Write a research grant proposal to the appropriate federal funding agency
c. Review the literature to determine what other research is available on this topic to Distribute a letter of consent to human subjects who will be used in the research.