The correct option is B.
The second industrial revolution occurred between 1870 and 1914. During this period, there was massive advancement in technology and in factories and this made it possible for manufacturers to produce a lot of goods en mass. The industrial revolution started in Britain and rapidly spread to Europe and North America an then to the rest of the world.
A)a new defensive tactic known as trench warfare
Trench warfare allowed the war to drag on for long periods of time because of the stalemates that ensue from the opposing armies refusing to give up the land under their controls, resulting in high casualties in no man's land.
Hope this helps
Answer: B
Explanation:He alqways started