To achieve specific goals rather than the total defeat of the enemy
Chlorine and Mustard gas are types of poison gas, sometimes used during chemical warfare. For example Germany introduced their usage against the Allies during WW1.
Answer:
Not A
Not B
Not C
Definitely D for the reason that they weren't given all their freedoms that the citizens had. A lot of people opposed immigrants and minorities back then, some still do and it's saddening.