The scientific method is systematic, which means
a. potential external influences are taken into account so as to not to influence the primary relationship.
b. the method is open to rigorous evaluation by the researcher and other scientists to ensure the reliability of conclusions.
c. the relationship of interest is examined methodologically under various settings and conditions.
d. the relationship of interest is based on observation, providing objective evidence to support the relationship being tested.
e. All of the above.