Answer:
d. not valid
Step-by-step explanation:
In the scientific method an experiment is a set of actions about phenomena. The experiment is fundamental in the empirical approach to the acquisition of a deeper knowledge about the physical world. Depending on the philosophical perspective an experience can lead to objective and complete understanding of the physical world or just an aid in improving subjective knowledge through fallibilism. Dr. Sigma's statement about a chemical that if taken internally once a day will prevent the common cold, must have come about through a scientific experiment. However, Dr Sigma's conclusions cannot be considered valid.
This is because, for the conclusions made through an experiment to be considered valid and correct, other scientists must be able to duplicate the results. No scientist has been able to duplicate the results found by Dr. Sigma, so we can conclude that Dr. Sigma's statement is invalid.