Which of the Following Best Defines Synergy

Which of the following best defines synergy?

A) the tendency of a closed system to lose its ability to control itself and thus to dissolve and disintegrate
B) a system that is self-contained and thus not affected by changes occurring in its external environment
C) the performance gains that result when individuals and departments work together
D) the set of forces and conditions that operate beyond an organization's boundaries
E) an approach to management that uses rigorous quantitative techniques