Answer:
the correct answer is Oil
Step-by-step explanation:
during the 1930's and after the wall street crash, USA entered the great depression that will last almost the entire decade and during this time, the global demand for energy and oil dipped as well. because of this decrease in demand, the oil prices went down.
in addition, a main reason for the decrease of demand was that during this time, the Europe, then the highest energy/oil consuming region was in an economic recession because of the events after the 1st world war and the rise of fascism.
moreover, the discovery of new oil resources in texas led to overproduction of oil as well.