According to Waltz, an understanding of international politics requires

a. a systems theory that incorporates economic factors into its concept of international politics.
b. a systems theory that incorporates social factors in its concept of international politics.
c. a systems theory that incorporates questions regarding the military interactions of states.
d. a systems theory that treats international politics as a distinct system.
e. a systems theory that addresses the ideological commitments of states.

Answer: d