Which of the following is an example of nationalism? A. A leader calls on his country's allies to protect his country from a threat posed by a neighboring nation-state. B. One country declares war on another power after that power invades the first country's ally. C. An activist organizes a protest of ethnic minorities in a country to demand that they be given their own country. D. Under an alliance, one country promises to defend another country from an attack by a third.