Which of the Following Examples Employs Realist Logic

Which of the following examples employs realist logic?

A) The United States invaded Iraq to remove the threat of weapons of mass destruction,which were a security risk.
B) The United States invaded Iraq because it was afraid that the United Nations would stop the war from happening.
C) The United States invaded Iraq because multinational corporations wanted access to Iraq's oil.
D) The United States invaded Iraq because Saddam Hussein did not find the threats of the United States to be credible.