Why Do Realists Believe That the Anarchic International System Leads

Why do realists believe that the anarchic international system leads to war?

A) The imperatives of capitalism cause states to expand in search of additional markets.
B) There are few rules about how to decide among contending claims and no effective arbiter to do so.
C) Anarchy encourages nonliberal governments to assume control of states and such states are more aggressive than democracies.
D) Anarchy encourages every country to attempt to become the world's government.
E) Anarchy leads countries to have weak armies, so they are attacked by terrorists.