New weapons such as poison gas, ___ were introduced during world war one

[twilight lover :)]

that changed how war was fought.? sorry again for my stupidness....

here are the choices:

a cannons and pistols
b machine guns and submarines
c trenches and rifles
d railroads and rationing

 

[Anime Dude]

choice "A" were already in use since before the civil war. choice"B" i believe machine guns were develpoed before ww1 and submarines were developed during the civil war but were called ironclads. choice "C" trenches was a battle technique used in ww1, opposing forces fought from trenches and the space in between was called "no mans land" and rifles were in use before the civil war. and choice "D" railroads were in use before before the civil war and rationing was also in use during the civil war. tanks, Poison gas, planes, torpedoes, and zeppelins (air ships) were introduced during ww1.