Which of the Following Best Describes the Term "Efficiency

Which of the following best describes the term "efficiency"?

A) The science and study of the causes of disease and their modes of operation
B) Ejection of the substance or metabolites from the body
C) The ability of a program to produce a desired effect among those who participate in the program compared with those who do not
D) The ability of a program to produce benefits among those who are offered the program