How Does Overdependence on a Few Staple Foods Increase the Risk

How does overdependence on a few staple foods increase the risk of famine?

A) The fewer the staple crops, the greater the danger to the food supply posed by crop failure.
B) Those staple foods are often also the ones used for trade.
C) Staple foods have fewer calories than other foods, which can lead to shortages.
D) Staple foods tend to be high-status foods, which leads to disputes.