What is the definition of pharmacodynamics?

A. This option refers to pharmaceutical formulation, not pharmacodynamics. B. This description pertains to pharmacokinetics, which involves drug absorption, distribution, metabolism, and elimination. C. Pharmacodynamics is defined as the study of how drugs interact with specific drug receptors to produce a physiological response, explaining the effects of drugs on the body. D. This option relates to drug development and testing rather than the specific interactions of drugs within the body.