Answer: C) To provide for a defense pact against possible Soviet attack
Explanation: When, after the Second World War, the Soviet Union began with its influence in the Eastern European countries, and the introduction of communist regimes in those countries, Western Allies saw the danger of a possible spread of Communism. So in 1949, NATO was formed, North Atlantic Treaty Organization, to ensure collective security and to respond to the influence of the Soviet Union. NATO consisted of United States, Canada and several Western European countries. Today, the number of member states is much higher.
The main reason why the US joined the war was because multiple attack on passenger and merchant ships with submarine attacks .The final straw was when the RMS Lusitania by a German u-boat going to Liverpool England .
Trench warfare was widely used at the beginning of the war but as it progresses modern military tactics such as infiltration tactics using small groups were used
