The 17th parallel was the provisional military demarcation line between North and South Vietnam established by the Geneva Accords of 1954.
Between russia and Ukraine......probably
President Eisenhower's threat to use atomic weapons probably deterred all of the following except "<span>a. the Vietnamese ousting their" government, since this threat was only meant to be made in the context of the Cold War. </span>
Germany fought Russia/USSR and France in both world wars. Both Italy and Japan where aligned with Third Reich in WW2, but fought against Germany in WW1. Italy did align itself with the German Empire in the years leading up to WW1, so that is the best answer out of all of these. However none of them are truly correct.