Which method offers the most reliable way of assessing whether athletic performance is boosted by drinking soda with caffeine in it?

A) the survey
B) the case study
C) the experiment
D) naturalistic observation

The most reliable method for assessing whether athletic performance is boosted by drinking soda with caffeine in it is the experiment. In an experiment, a group of athletes can be randomly assigned to either drink soda with caffeine or a placebo, and then their athletic performance can be tested and compared. This method allows for control of variables and for causal conclusions to be made. Surveys, case studies, and naturalistic observations may provide some information, but they do not offer the same level of control or ability to make causal claims.