The correct options are
C Rice production was abundant during the American Civil war.
D Tax amounts were changed every year based on the current situations.
As commercialisation increased, there was a demand for cash crops like cotton. This was observed during the American civil war where India became highly sought after for cotton. This resulted in a decrease in essential crops like rice and peasants could not make money with the leftover cotton. Tax amounts were fixed for 20-30 years and changed on after its tenure.