Answer:
The correct answer is B. World War I.
Step-by-step explanation:
A trench warfare is a war in which both sides have dug themselves opposite each other in trenches and other fortified positions, with the aim of halting the advance of the enemy, which culminates in a stalemate where neither side succeeds in breaking through the enemy lines. The best-known trench warfare is World War I.
In general, trench warfare is the result of technological advances that allow enemy soldiers to be killed faster than they can advance. For example, in World War I, repeating rifles, machine guns, and modern artillery made it possible to mow down soldiers in the open by bushes. However, as armies still moved largely on foot and horseback, they could not cross those same open battlefields fast enough to get close enough to the enemy and fire effectively at the enemy.