As fought in the World War I, trench warfarea. became a senseless slaughter of troops on all sides with hundreds of thousands of mendying for battlefield gains of a few miles.b. increased the morale of soldiers who fought well and came to obey promptly the ordersof their superiors.c. became increasingly unreal as baffled and incompetent officers persistently ordered theirmen to accomplish battlefield objectives that were impossible.d. brought great innovations to military tactics as the long conflict forced generals to devisenovel tactics.