Which of These Is an Advantage and a Disadvantage of Rice

Which of these is an advantage and a disadvantage of rice as a staple crop?

A) It is does not need much water, but is difficult to preserve.
B) It does not require carefully-timed irrigation, but can only grow on hillsides.
C) It is labor-intensive, but cannot be made into flour.
D) It feeds many people per acre, but is labor-intensive.
E) It is requires less labor than other grains, but cannot be transported over long distances.