Which of the following statements best characterizes farming in the sahara?

a. there is no farming at all in the sahara.

b. there are isolated pockets of farming, generally around rivers and oases, which are used for irrigation.

c. there are no sources of irrigation, so people in the sahara depend on rainfall to water their crops.

d. there is widespread farming throughout the sahara region, as the climate is well suited for growing crops.