Which of the following directly caused France, Germany, and Russia to get involved in World War I?(1 point)

The direct cause that led to France, Germany, and Russia getting involved in World War I was **The alliance system**. The complex web of alliances in Europe, including treaties and agreements between countries, meant that once a conflict began, other nations were obligated to join due to their alliances. The assassination of Archduke Franz Ferdinand of Austria-Hungary triggered a series of events based on these alliances that escalated into a full-scale war.