A country's capacity to produce wealth depends on ______.

A．The US is the wealthiest country in the world while the Sahara Desert is the poorest region.
B．Some regions of the world are well supplied with natural resources while other regions possess none of them.
C．Some countries can better use natural resources while other countries have been unable to develop their resources.
D．The US has a sound and stable political condition while the Sahara Desert has suffered for many years from civil wars.

A．a country's wealth depends on many factors
B．the US is one of the wealthiest countries in the world
C．the Sahara Desert is a very poor region
D．natural resources is an important factor in the wealth or poverty of a country