Which led to the dust storms of the 1930s?

i am not 100   percent sure but i do know that hitler was burned to death with gas so that makes me think it is d. because they were under his control if they fail or not do as told they will be killed but i could be wrong hope this

to tell the truth it is a mix of the a and d because after the romans argued among themselves outside forces took control however it is mostly d.