Final answer:
The scientific method includes steps like making observations and conducting experiments, but epidemiological research is not considered one of its standard steps.
Step-by-step explanation:
The scientific method is a systematic process for conducting scientific investigations. It includes steps such as making observations, formulating a hypothesis, conducting an experiment to test the hypothesis, and then analyzing the results to draw conclusions. Out of the options provided (a. observation, b. hypothesis, c. epidemiological research, and d. experimentation), the step that is not generally considered a part of the core process of the scientific method is epidemiological research. While epidemiological research is important in the field of health and disease study, it is not a standard step in the base scientific method which can apply to all branches of science.